Face masks during the COVID-19 pandemic

During the COVID-19 pandemic, face masks or coverings, including N95, FFP2, surgical, and cloth masks, have been employed as public and personal health control measures against the spread of SARS-CoV-2, the virus that causes COVID-19.

US Ambassador to Indonesia Sung Kim accompanied by local officials at the Presidential Palace wearing face masks amid the COVID-19 pandemic

In community and healthcare settings, the use of face masks is intended as source control to limit transmission of the virus and for personal protection to prevent infection.[1] Properly worn masks both limit the respiratory droplets and aerosols spread by infected individuals and help protect healthy individuals from infection.[2][3]

Reviews of various kinds of scientific studies have concluded that masking is effective in protecting the individual against COVID-19.[2][4][5] Various case-control and population-based studies have also shown that increased levels of masking in a community reduces the spread of SARS-CoV-2,[4][5] though there is a paucity of evidence from randomized controlled trials (RCTs).[6][7] Masks vary in how well they work, with N95 and surgical masks outperforming cloth masks,[8] but even cloth masks, with their variability in fabric type and mask fit, provide wearers with substantial protection from particles carrying COVID-19.[9]

Among readily available fabrics, double-layered cotton, hybrid masks, and cotton flannel perform best,[9] and filtration effectiveness generally improves with thread count.[8] Healthcare workers, given their exposure, are recommended against using cloth masks.[9]

During the public health emergency, governments widely recommended and mandated mask-wearing, and prominent national and intergovernmental health agencies and their leaders recommended the use of masks to reduce transmission, including the WHO, American, European, and Chinese Centers for Disease Control and Prevention.

Types of masks edit

Many federal governmental agencies recommended using face masks to avoid COVID-19 transmission. Masks with exhalation valves were not recommended because they expelled the wearer's breath outwards, and an infected wearer would transmit the virus through the valve. A second purpose of face masks is to protect each wearer from environments that can infect them, which can be achieved by many models of masks.[10]

Various types of masks each provide different levels of protection against COVID-19 transmission, ease of use, and comfort:

There are some other types of personal protective equipment (PPE), such as face shields and medical goggles, which are sometimes used in conjunction with face masks but were not recommended as a replacement.[11] Other kinds of PPE include gloves, aprons, gowns, shoe covers, and hair covers.[12]

There have been shortages of masks, which have led to the use of uncertified masks, with worse performance.[13]

Cloth masks edit

Cloth face masks

A cloth face mask is worn over the mouth and nose and made of common textiles such as cotton. Masks vary widely in effectiveness, depending on factors such as material, fit and seal, and the number of layers. They are usually less effective at filtering than surgical masks and offer much less protection.[14][15] Unlike disposable masks, there are no required standards for cloth masks.[16]

One 2020 study found that a cloth mask was better than nothing, but not as good as a soft electret-filter surgical mask for protecting healthcare workers while simulating the treatment of an artificially infected patient.[16] Research on commonly available fabrics used in cloth masks found that cloth masks can provide significant protection against the transmission of particles in the aerosol size range, with enhanced performance across the nanoscale and microscale when masks use both mechanical and electrostatic-based filtration, but that leakage due to improper fit can degrade performance.[17] A review of available research published in January 2021 concludes that cloth masks are not considered adequate to protect healthcare practitioners in a clinical setting.[18]

A 2013 study had volunteers wear masks they made themselves from cotton T-shirts, following the pattern of a standard tie behind the head surgical mask,[19] and found the number of microscopic particles that leaked to the inside of the homemade masks was twice that of commercial masks. Wearing homemade masks also leaked a median average of three times as many microorganisms as commercial masks. But another 2020 study found that masks made of at least two layers of T-shirt fabric could be as protective against virus droplets as medical masks, and as breathable.[20]

World Health Organization infographic on how to wear a non-medical fabric mask safely[21]

A 2020 peer-reviewed summary of published literature on the filtration properties of cloth and cloth masks recommends two to four layers of plain-weave cotton or flannel of at least 100 threads per inch.[22] There is a trade-off in that increasing the number of layers increases the filtration of the material but decreases how easy it is for a person to breathe through the mask.[23]

As of May 2020, there was no research on decontaminating and reusing cloth masks.[16] The CDC recommends removing a mask by handling only the ear loops or ties, placing it directly in a washing machine, and immediately washing hands in soap and water for at least twenty seconds. Cold water is considered as effective as warm water for decontamination.[24] The CDC also recommends washing hands before putting on the mask and again immediately after touching it.[25]

There is no information on reusing an interlayer filter. Disposing of filters after a single use may be desirable.[16] A narrative review of the literature on the filtration properties of cloth and other household materials did not find support for using a filter. A layer of cloth, if tolerated, was suggested instead,[22] or a PM2.5 filter, as a third layer.[26]

The United States Environmental Protection Agency (EPA) Study published on 5 April 2021, showed extremely varied performance across cotton masks. The results of the EPA study found that "a three-layer knitted cotton mask blocked an average of 26.5 percent of particles in the chamber, while a washed, two-layer woven nylon mask with a filter insert and metal nose bridge blocked 79 percent of particles on average."[27] Ultimately, the researchers found that fabric and fit are the two most vital factors when recommending masks to the public and further research is being conducted on variables such as facial hair and face shape on mask fit.[27]

Surgical masks edit

World Health Organization infographic on how to wear a medical mask safely[21]

A surgical mask is a loose-fitting, disposable mask that creates a physical barrier separating the mouth and nose of the wearer from potential contaminants in the immediate environment. If worn properly, a surgical mask is meant to help block large-particle droplets, splashes, sprays, or splatter that may contain viruses and bacteria, keeping them from reaching the wearer's mouth and nose. Surgical masks may also help reduce exposure of others to the wearer's saliva and respiratory secretions.[28][29]

Taiwanese president Tsai Ing-wen wearing a surgical mask

Certified medical masks are made of non-woven material, and they are mostly multi-layer. Filters may be made of microfibers with an electrostatic charge; that is, the fibers are electrets. An electret filter increases the chances that smaller particles will veer and hit a fiber, rather than going straight through (electrostatic capture).[30][31][32][better source needed][medical citation needed] While there is some development work on making electret filtering materials that can be washed and reused,[33] current commercially produced electret filters are ruined by many forms of disinfection, including washing with soap and water or alcohol, which destroys the electric charge.[34] During the COVID-19 pandemic, public health authorities issued guidelines on how to save, disinfect and reuse electret-filter masks without damaging the filtration efficiency.[34][35] Standard disposable surgical masks are not designed to be washed. Surgical masks may be labeled as surgical, isolation, dental, or medical procedure masks.[28] The material surgical masks are made from is much poorer at filtering very small particles (in the range of a tenth of a micrometer to a micrometer across) than that of filtering respirators (for example N95, FFP2) and the fit is much poorer.[28] Surgical masks are made of a non-woven fabric created using a melt blowing process.[36][37] Random control studies of respiratory infections like influenza find little difference in protection between surgical masks and respirators (such as N95 or FFP masks).[38] However, the filtering performance of correctly worn N95/FFP2 type filtering respirators is clearly superior to surgical and to cloth masks[15] and for influenza, work by the UK Health and Safety executive[39] found that live virus penetrated all surgical masks tested but properly fitted respirators reduced the viral dose by a factor of at least a hundred.

Surgical masks made to different standards in different regions of the world have different ranges of particles which they filter. For example, the People's Republic of China regulates two types of such masks: single-use medical masks (Chinese standard YY/T 0969) and surgical masks (YY 0469). The latter ones are required to filter bacteria-sized particles (BFE ≥ 95%) and some virus-sized particles (PFE ≥ 30%), while the former ones are required to only filter bacteria-sized particles.[40][41][42]

Modifications edit

The effectiveness of surgical masks in limiting particle transmission is a function of material and fit.[43] Since the start of the pandemic, scientists have evaluated various modifications to ear loop surgical masks aimed at improving mask efficacy by reducing or eliminating gaps between the mask and face.[44] The CDC evaluated and recommended two such modifications to ear loop masks to minimize the transmission of SARS-CoV-2. Under regular use, the CDC found that a surgical mask worn by a coughing individual blocked 41.3% of simulated cough aerosols (0.1–7.0 μm particle size) from reaching a second individual six feet away. However, by applying a knot and tuck technique,[a] 62.9% of particles were blocked. When the surgical mask was covered with a larger cloth mask, 82% of the particles were blocked. When both the source and recipient wore masks, 84% of the particles were blocked. The number increased to more than 95% when both parties either wore double masks (surgical mask with larger cloth mask) or used the knot and tuck technique.[45]

Another type of modification was aimed to improve the comfort of the wearers. Early in the pandemic, healthcare workers were required to continue wearing surgical masks for 12 or more hours a day. This caused the ear loops of the masks to chafe the back of their ears. Ear savers, plastic straps, and hooks that go around wearer's heads, were invented to move the ear loops away from the wearer's ears. They could be made on demand by using a 3D printing process.[46]

An improved version approaches the model efficacy of N95 respirators.[47]

Filtering respirators edit

N95 mask

An N95 mask is a particulate-filtering facepiece respirator that meets the N95 air filtration rating of the US National Institute for Occupational Safety and Health, meaning it filters at least 95 percent of 0.3 μm airborne particles, while not resistant to oil like the P95. It is the most common particulate-filtering facepiece respirator.[48] It is an example of a mechanical filter respirator, which provides protection against particulates, but not gases or vapors.[49] Like the middle layer of[50] surgical masks, the N95 mask is made of four layers[16] of melt-blown nonwoven polypropylene fabric.[51][52][unreliable medical source?] The corresponding face mask used in the European Union is the FFP2 respirator.[53][54]

Hard electret-filter masks like N95 and FFP masks must fit the face to provide full protection. Untrained users often get a reasonable fit, but fewer than one in four gets a perfect fit. Fit testing is thus standard, though debated.[55][56] A line of petroleum jelly on the edge of the mask[57] has been shown to reduce edge leakage[16] in lab tests using mannequins that simulate breathing.[57]

Some N95 series respirators, especially those intended for industrial use, have an exhalation valve to improve comfort, making exhalation easier and reducing leakage on exhalation and steaming up of glasses. But those respirators are not reliable for the control of infected people (source control) in respiratory diseases such as COVID-19, because infected users (asymptomatic or not) would transmit the virus to others through the valve.[58]

During the COVID-19 pandemic, there were shortages of filtering facepiece respirators, and they had to be used for extended periods, and/or disinfected and reused. At the time, public health authorities issued guidelines on how to save, disinfect and reuse masks, as some disinfection methods damaged their filtration efficiency.[34][35] Some hospitals stockpiled used masks as a precaution,[59] and some had to sanitize and reuse masks.

Face shields and eye protection edit

A medical worker wearing a face shield adjunct to other personal protective equipment at a COVID-19 testing site

The US Centers for Disease Control and Prevention (CDC) does not recommend the use of face shields as a substitute for masks to help slow the spread of COVID-19.[60] In a study by Lindsley et al. (7 January 2021) funded by the National Institute for Occupational Safety and Health, part of the CDC, face shields were found to block very few cough aerosols in contrast to face coverings – such as cloth masks, procedure masks, and N95 respirators – indicating that face shields are not effective as source control devices for small respiratory aerosols and that face coverings are more effective than face shields as source control devices to reduce the community transmission of SARS-CoV-2.[61]

In a scoping review, Godoy et al. (5 May 2020) said face shields are used for barrier protection against splash and splatter contamination but should not be used as primary protection against respiratory disease transmission due to the lack of a peripheral seal rather than as an adjunct to other facial protection.[16] They remarked that face shields have been used like this alongside medical-grade masks during the COVID-19 pandemic.[16] They cited a cough simulation study by Lindsley et al. (2014) in which face shields were shown to reduce the risk of inhalation exposure up to 95% immediately following aerosol production, but the protection was decreased with smaller aerosol particles and persistent airborne particles around the sides.[62]

There is weak evidence that the use of eye protection including face shields is associated with less infection.[63]

Elastomeric respirators edit

Surgeons wearing full-facepiece elastomeric respirators while doing tracheostomy to a COVID-19 patient in Russia

Elastomeric respirators are reusable personal protective equipment comprising a tight-fitting half-facepiece or full-facepiece respirator with exchangeable filters such as cartridge filters.[64] They provide an alternative respiratory protection option to filtering facepiece respirators such as N95 masks. Some healthcare workers have used them during times of short supply caused by the pandemic, as they can be reused over an extended period in healthcare settings.[64][65] However, most elastomeric respirators have an unfiltered exhalation vent which would allow the virus to spread from the wearer.[65]

For the COVID-19 response when supplies are short, the US CDC says contingency and crisis strategies should be followed: Each elastomeric respirator is issued for the exclusive use of an individual healthcare provider but must be cleaned and disinfected as often as necessary to remain unspoiled and sanitary. If there is no other option than to share a respirator between healthcare providers, the respirator must be cleaned and disinfected before it is worn by a different individual. Filters (except for unprotected disc types) may be used for an extended period, but the filter housing of cartridge types must be disinfected after each patient interaction.[64]

Powered air-purifying respirators edit

A powered air-purifying respirator (PAPR) is a personal protective equipment in which a device with a filter and fan creates a highly filtered airflow towards the headpiece and a positive outflow of air from the headpiece.[66]

There is an increased risk for healthcare workers to become exposed to SARS-CoV-2 when they conduct aerosol-generating procedures on COVID-19 patients, which is why it is argued that such situations may require enhanced personal protective equipment (i.e., higher than N95) such as PAPRs for healthcare workers.[66][67]

In a systematic review, Licina, Silvers, and Stuart (8 August 2020) said field studies indicate that there were equivalent rates of infection among healthcare workers who performed airway procedures on critical COVID-19 patients using PAPRs or other appropriate respiratory equipment (such as N95 or FFP2), but remarked that there is a need to further collect field data about optimal respiratory protection during highly virulent pandemics.[68]

Face masks with exhalation valves edit

Flow visualizations comparing face mask efficacy with and without exhalation valve, illustrating the concern that exhalation valves allow exhaled respiratory droplets to reach others in proximity and would therefore not be appropriate in source control strategies[69]

Some masks include an exhalation valve to expel the breath outwards, but that airflow is not filtered. Certification (as N95 or FFP2) is about the mask itself and does not warrant any safety about the air that is exhaled. Putting tape over the exhalation valve can make a mask or respirator as effective as one without a valve.[70]

Scientists have visualized droplet dispersal for masks with exhalation valves and face shields and concluded that they can be ineffective against COVID-19 spread (e.g., after a cough) and recommended alternatives.[71][72]

Recommendations edit

The use of face masks or coverings by the general public has been recommended by health officials to minimize the risk of transmissions, with authorities either requiring their use in certain settings, such as on public transport and in shops, or universally in public.

Health officials had advised that medical-grade face masks, such as respirators, should be prioritized for use by healthcare workers in view of critical shortages, so they used to generally first and foremost recommend cloth masks for the general public.[73][74] However, recommendations have changed as the body of scientific knowledge evolved.[75] Scientists now recommend having a triple-layered surgical mask and a respirator.[76]

According to #Masks4All, in September 2020, approximately 95% of the world population lived in a country where the government and leading disease experts recommend or require the use of masks in public places to limit the spread of COVID-19.[77]

World Health Organization edit

A video from the World Health Organization regarding different types of face masks and how to use them

Early in 2020, the WHO had only recommended medical masks for people with suspected infection and respiratory symptoms, their caregivers and those sharing living space, and healthcare workers.[78][79][80] In April 2020, the WHO acknowledged that wearing a medical mask can limit the spread of certain respiratory viral diseases including COVID-19 but claimed that medical masks would create a false sense of security and neglect of other necessary measures, such as hand hygiene.[80]

The early WHO advice on limited mask usage was scrutinized for several reasons. First, experts and researchers pointed out the asymptomatic transmission of the virus.[81][82][83][84][85] Second, according to Marteau et al. (27 July 2020), available evidence does not support the notion that masking adversely affects hand hygiene:[86] Dame Theresa Marteau, one of the researchers, remarked that "The concept of risk compensation, rather than risk compensation itself, seems the greater threat to public health through delaying potentially effective interventions that can help prevent the spread of disease."[87]

The WHO revised its mask guidance in June 2020, with its officials acknowledging that studies indicated asymptomatic or pre-symptomatic spread.[88] The updated advice recommended that the general public should wear non-medical fabric masks where there is known or suspected widespread transmission and where physical distancing is not possible, and that vulnerable people (60 and over, or with underlying health risks) and people with any symptoms suggestive of COVID-19 as well as caregivers and healthcare workers should wear surgical or procedure masks.[74] They stated that the purpose of mask usage is to prevent the wearer transmitting the virus to others (source control) and to offer protection to healthy wearers against infection (prevention).[74]

The WHO advises that non-medical fabric masks should comprise a minimum of three layers,[74] suggesting an inner layer made of absorbent material (such as cotton), a middle layer made of non-woven material (such as polypropylene) which may enhance filtration or retain droplets, and an outer layer made of non-absorbent material (such as polyester or its blends) which may limit external contamination from penetration.[89]

On 21 August 2020, the WHO and UNICEF released an annex guidance for children.[90] For children five and younger, they advise that masks should not be required in consideration to a child's developmental milestones, compliance challenges, and autonomy required to use a mask properly, but recognized that the evidence supporting their cut-off age is limited and countries may hold a different and lower age of cut-off.[90] For children 6–11, they advise that mask usage should be decided in consideration of several factors including the intensity of local viral transmission, (the latest evidence about) the risk of infection for the age group, the social and cultural environment (which influences social interactions in communities and populations), the capacity to comply with appropriate mask usage, the availability of appropriate adult supervision, and the potential impact on learning and psychosocial development, as well as additional factors involving specific settings or circumstances (such as disabilities, underlying diseases, elderly people, sport activities, and schools).[90] For children 12 and older, they advise that masks should be worn under the same conditions for adults in accordance with WHO guidance or national guidelines.[90]

Regarding the use of non-medical fabric masks in the general population, the WHO has stated that high-quality evidence for its widespread use is limited, but advises governments to encourage its use as physical distancing may not be possible in some settings, there is some evidence for asymptomatic transmission, and masks could be helpful to provide a barrier to limit the spread of potentially infectious droplets.[91]

United States Centers for Disease Control and Prevention edit

Guidance from the US Centers for Disease Control and Prevention on using and making cloth masks during the COVID-19 pandemic[92]

Early in 2020, the United States Centers for Disease Control and Prevention (CDC) said it did not recommend the use of face masks for the general public.[93][94] However, on 3 April 2020, the CDC changed its advice to recommend that people wear cloth face coverings "in public settings when around people outside their household, especially when social distancing measures are difficult to maintain".[95][96] In response to a media inquiry by National Public Radio, the CDC said that this change in guidelines was due to the increasing and widespread transmission of the virus, citing studies published in February and March showing pre-symptomatic and asymptomatic transmission.[97] In a subsequent interview and JAMA editorial, the CDC director Robert R. Redfield explained that the CDC's early guidance had been premised on an initial absence of evidence of disease transmission from pre- and asymptomatic individuals.[98][99][100]

The CDC does not recommend masks with exhalation valves or vents for source control.[60] In the healthcare workers' guidance, if only respirators with valves are available and source control is needed, the CDC recommends that the valve should be covered with a surgical mask, procedure mask, or cloth face covering.[101]

On 28 June, the CDC stated the "CDC recommends that people wear cloth face coverings in public settings and when around people who don't live in your household, especially when other social distancing measures are difficult to maintain. Cloth face coverings may help prevent people who have COVID-19 from spreading the virus to others. Cloth face coverings are most likely to reduce the spread of COVID-19 when they are widely used by people in public settings."[102] The CDC provided the caveat that cloth face coverings should not be worn by children under the age of two, people who have trouble breathing, or people who are unconscious, incapacitated, or otherwise unable to remove the mask without assistance.[102] In August 2020, the CDC added that exhalation valves or vents in masks do not help prevent the person wearing the mask from spreading COVID-19 to others.[60][103]

In a November 2020 scientific brief, the CDC reiterated their recommendation for the community use of masks and specifically non-valved multi-layer cloth masks to prevent transmission of SARS-CoV-2.[104] They say the community's use of masks serves two primary purposes: to reduce the emission of virus-laden droplets from exhalation into the environment (source control), which is especially relevant for asymptomatic or pre-symptomatic infected wearers who feel well and may be unaware of their infectiousness to others, and to reduce inhalation of these droplets through filtration for the wearer (personal protection).[104] For filtration, the CDC says some fabrics (such as silk) may hydrophobically repel moist droplets, whereas other fabrics (such as polyester or polypropylene) may electrostatically capture droplets.[104] They concluded that the benefit of masking for SARS-CoV-2 control is derived from the combination of source control and personal protection, which is likely complementary and possibly synergistic so that individual benefit increases with increasing community mask use.[104]

The CDC said healthcare personnel should wear a NIOSH-approved N95 (or equivalent or higher-level) respirator or a face mask (if a respirator is not available) with a face shield or goggles as part of their personal protective equipment, while patients with suspected or confirmed SARS-CoV-2 infection should wear a face mask or cloth face covering during transport.[105] As crisis strategy for known shortages of N95 respirators in healthcare settings, among other sequential measures, the CDC suggests use of respirators beyond the manufacturer-designated shelf life, use of respirators approved under standards used in other countries that are similar to NIOSH-approved respirators, limited re-use of respirators, use of additional respirators beyond the manufacturer-designated shelf life that have not been evaluated by NIOSH, and prioritizing the use of respirators and face masks by activity type.[106]

In late July 2021, the CDC changed guidelines to recommend people, including those who are vaccinated, to continue masking in public indoor settings in areas with substantial and high transmission—as there are indications that the coronavirus such as the Delta variant may infect even vaccinated people in rare occasions—to help prevent transmission to other people.[107][108] Previously, the CDC updated public guidance from May 2021 stated that those who are fully vaccinated can "resume activities without wearing masks or physically distancing, except where required by federal, state, local, tribal, or territorial laws, rules and regulations, including local business and workplace guidance."[109] However, critics posited that it was predicated on a key social factor, namely whether people can be trusted to wear a mask if they are not fully vaccinated.[110][111][112]

On 25 February 2022, the CDC changed its guidelines to suggest that 70% of Americans need no longer wear masks, and no longer need to social distance or avoid crowded spaces.[113] Under the new guidance, Americans in counties designated as medium-to-low-risk can go indoors without masks. In accordance with these new CDC guidelines, a number of US states ended their mask mandates for indoor spaces. However, federal officials emphasized that regardless of local conditions, individuals with COVID-19 or COVID-19 symptoms, as well as individuals who consider themselves to be high-risk, should continue to wear facial coverings. In addition to this, the CDC also dropped its recommendation for universal school mask mandates.[114] These new recommendations assessed COVID-19 hospitalizations as well as the proportion of beds occupied by COVID-19 patients in certain areas.

Criticism of guidance edit

Larry Gostin, a professor of public health law, said initial CDC and WHO guidance had given the public the wrong impression that masks do not work, even though scientific evidence to the contrary was already available.[97] The confusing changing advice from discouraging to recommending public masking has led to decreasing public trust in the CDC.[83][115] In June 2020 Anthony Fauci, a leading infectious disease expert for the United States government, stated that the delay in recommending general mask use was motivated by a desire to conserve dwindling supplies for medical professionals.[116] Since September 2021, the director of the CDC, Rochelle Walensky, indicated that the schools that did not have mask mandates were 3.5 times as likely to experience COVID outbreaks as the ones that did. This statement caused controversy because the basis for it was an outlier study criticized by some experts as unreliable and basically useless to learn about the effects of mask mandates.[117]

China edit

In March 2020, when asked about the mistakes that other countries were making during the pandemic, the Chinese Center for Disease Control and Prevention director-general George Fu Gao said:

The big mistake in the U.S. and Europe, in my opinion, is that people aren't wearing masks. This virus is transmitted by droplets and close contact. Droplets play a very important role – you've got to wear a mask because when you speak, there are always droplets coming out of your mouth. Many people have asymptomatic or pre-symptomatic infections. If they are wearing face masks, it can prevent droplets that carry the virus from escaping and infecting others.[118]

Europe edit

Masked participants in the 2020 edition of the Mille Miglia road race in Brescia, Italy

Most countries in Europe introduced mandatory face mask rules for public places.[119][120] On 8 April 2020, the European Centre for Disease Prevention and Control (ECDC) published its masking recommendations, saying that the "use of face masks in the community could be considered, especially when visiting busy, closed spaces".[121][73] On 15 February 2021, ECDC updated the recommendation stating, "Although the evidence for the use of medical face masks in the community to prevent COVID-19 is limited, face masks should be considered as a non-pharmaceutical intervention in combination with other measures as part of efforts to control the COVID-19 pandemic."[122]

The Nordic countries and the Netherlands have been a notable exceptions in supporting the use of face masks,[120][123] but eventually started to recommend masks. For example, due to the COVID-19 pandemic in the Netherlands, wearing a mouth/nose mask was made mandatory on public transportation per 1 June 2020.[124] The main reasoning against masks recommendations given by officials in the Nordic countries was that public masking is deemed an unnecessary precaution when infection levels remain low.[125] In June 2020, the Norwegian Institute of Public Health said asymptomatic individuals wearing face masks were not to be recommended due to the low prevalence of COVID-19 in the country but noted that it should be reconsidered if cases rise.[126] Similarly, on 30 July 2020, the Danish Health Authority director Søren Brostrøm said face covers did not make sense in the current situation with low infection levels, but that they needed to evaluate whether it could make sense in the long term.[127][128]

Sweden was notable as a country where face masks were not recommended to the general public and the State Epidemiologist of Sweden, Anders Tegnell, was an opponent to face masks among the general population, although he stated that face masks might be suitable in workplaces where people are one to two meters from each other for more than fifteen minutes, something which some Swedish and foreign media have interpreted as a recommendation.[129][130] This position was slightly reversed when Prime Minister of Sweden, Stefan Löfven, announced that they were recommending face masks on 18 December 2020.[131] The Public Health Agency of Sweden later clarified on their website that the recommendation would include citizens born before 2004 to wear masks during rush hour on public transportation throughout the country from 7 January 2021 onward.[132] On 20 December 2020, two days after the announcement was made, Prime Minister Löfven was paparazzied in a shopping mall in central Stockholm without wearing a face mask.[133] By 22 January 2021, the Stockholm Public Transport estimated that about half of all passengers on trains and buses wore face masks during rush hour.[134] Among those who chose not to follow the recommendation were Johan Carlson, the Director-General of the Public Health Agency, and Anders Tegnell, the state epidemiologist.[135][136]

Rationale edit

Schlieren image showing the interaction of exhaled airflows between two people[137]

Masks are used to limit the transmission of SARS-CoV-2 by respiratory droplets and aerosols, which are thought to be the major pathways of infection, exhaled from infected individuals during breathing, speaking, coughing, and sneezing.[1][138][139] Properly worn masks are effective in both limiting the spread of the virus by an infected individual and protecting an uninfected individual from infection.[3]

The National Health Commission of China cited the following reasons for the wearing of masks by the public, including healthy individuals:

  1. Asymptomatic transmission. Many people can be infected without symptoms or only with mild symptoms.[140]
  2. Difficulty or impossibility of appropriate social distancing in many public places at all times.[140]
  3. Cost-benefit mismatch. If only infected individuals wear masks, they would have a negative incentive to do so. An infected individual might get nothing positive, but only bear the costs such as inconvenience, purchasing expenses, and even prejudice.[140]
  4. There is no shortage of masks in China. The country has the production capacity to meet the demand for masks.[140]

Source control edit

In a comment to The Lancet, Kar Keung Cheng, Tai Hing Lam, and Chi Chiu Leung argued that a public health rationale for mass masking is source control to protect others from respiratory droplets and underscored the importance of this approach due to asymptomatic transmission.[141] Wang Linfa, an infectious disease expert who heads a joint Duke University and National University of Singapore research team, said masking is about "preventing the spread of disease rather than preventing getting the disease", remarking that the point is to cover the faces of people who are infected but do not know it, so it is imperative for everyone to wear one in public.[82] The US CDC also highlighted the use of masks for source control, pointing out that asymptomatic and pre-symptomatic cases are estimated to account for over 50% of the transmissions.[142]

Respiratory tract edit

Monica Gandhi, a medical professor at the University of California, San Francisco, says viral shedding at high quantities from the upper respiratory tract, characterized by unusually high levels of viral particles, means universal mask wearing is one of the best ways to limit the asymptomatic spread of the virus.[143] Yixuan Hou et al. (July 2020) found that the nasal cavity is the dominant initial site for SARS-CoV-2 infection with subsequent aspiration-mediated virus seeding into the lungs; the authors note that these findings argue for the widespread use of masks to prevent exposure to the nasal passages.[144]

Severity edit

In a perspective, Monica Gandhi, Chris Beyrer, and Eric Goosby posit that masking reduces the dose of the virus for the wearer and thus helps lower the severity of infection.[145] They highlighted that the proportion of asymptomatic and mild infection increased in settings adopting population-level masking.[145] One example involved a comparison of outbreaks on cruise ships: the Diamond Princess had 18% asymptomatic cases among all the infected people, but this was 81% in the Greg Mortimer where masks were given to passengers and staff members.[145]

Precautionary edit

Trisha Greenhalgh et al. argue for the precautionary principle as a reason to adopt policies encouraging the wearing of face masks in public, given that there's much to gain and little to lose from adopting masks considering the seriousness of the outbreak.[146] Others agreed, based on the evidence-based principle that the likely benefits outweighed the likely harms.[147][148]

Distancing edit

Leonardo Setti et al. argue that face masks should be used to complement social distancing of six feet or two meters, because this inter-personal distance is more effective if people are masked as studies indicate that SARS-CoV-2 could be transmitted over greater distances.[149] Chi Chiu Leung et al. also argue that face masks complement social distancing, as a high degree of compliance for distancing is necessary to achieve the greatest impact but is not always achievable.[150] For instance, even if social distancing is rigorously practiced, there are necessary person-to-person contacts (such as going to the supermarket and other necessary activities to sustain livelihoods), so masks would help in situations when social distancing is not feasible and maximize the effectiveness of social distancing.[150]

Touching edit

According to Stephen Griffin, a virologist at the University of Leeds, "Wearing a mask can reduce the propensity for people to touch their faces, which is a major source of infection without proper hand hygiene."[151] Ka Hung Chan and Kwok-Yung Yuen argue that face masks can reduce fomite transmission (in addition to the transmission through droplets or aerosol) of the virus, as masks can prevent people from spreading body fluids by touching their noses or mouths (such as trying to cover up a sneeze or cough).[152]

A paper by Miyu Moriyama et al. (September 2020), which links the seasonality of respiratory viral diseases to decreased air humidity due to indoor heating, argues that mask-wearing helps limit respiratory virus transmission in winter because masks keep the nose warm and moist.[153]

Social media claims that masks could reduce the oxygen levels in older people were refuted by a small study of SpO2 levels, the results of which were published by JAMA.[154]

Efficacy edit

Overall edit

There are two types of evidence for the efficacy of masks: observational studies, and randomised controlled trials (RCTs). While RCTs are more robust, they are too impractical for many public health interventions, yielding insufficient statistical power and validity.[155] Most of the evidence for the efficacy of masks against COVID comes from observational studies.[156] Due to the paucity of evidence from RCTs, some systematic reviews have included the observational studies along with the RCTs.[7][4] As of August 2023, RCTs played a relatively small role in the evaluation of non-pharmaceutical interventions during the pandemic.[156]

A 2023 systematic review from the Cochrane Collaboration said the evidence from randomized controlled trials was still inconclusive over whether masking prevented the spread of influenza/COVID‐like illness through a population, noting that the answer could be different for different viruses.[6] This Cochrane review was criticized for combining studies about influenza and about COVID, which could "yield invalid conclusions".[155] Another 2023 systematic review, by the Royal Society, found the evidence from RCTs was that masks reduced risk by 12% to 18%.[7]

A 2022 systematic review and meta-analysis of randomized controlled trials on face mask use in PLOS One showed that with 95% confidence, masks reduced respiratory infection incidence by between 3% and 19% in a community setting.[157] A 2023 article in JAMA Network Open found that "robust data" support the use of face masks to reduce community transmission of COVID.[155] A 2023 review in Archives of Disease in Childhood on mask wearing by children found no good clinical evidence that mask wearing was of benefit for them in preventing COVID-19 transmission or infection.[158]

A systematic review and meta-analysis of the effectiveness of masks published in The BMJ in November 2021 showed that with 95% confidence, masks reduced COVID incidence by between 25% and 71%. This result is based on six primary studies. These studies were of several different types: case-control studies in Thailand and three Western countries (where cases identified whether they were wearing a mask when they had contact with a known positive patient), a randomized control study in Denmark which assessed the impact on mask-wearing on the wearer, a natural experiment that compared US states that implemented mask mandates on the level of COVID, a cross-sectional comparative study in China which surveyed whether a mask protected the wearer, and a retrospective cohort study in China which assessed the impact of masks worn by infected and uninfected family members. Another five studies were not included because they were not directly comparable. They assessed the impact of mask mandates across countries on mortality (finding a 45.7% reduction), of mask mandates in the US on R (finding a 29% reduction), a comparative incidence of COVID associated with mask-wearing comparing HK and South Korea (finding a significant reduction), a natural experiment across US states finding a significant effect on case rates, and a cross-sectional study assessing a 10% increase in mask wearing led to a 71% reduction in the risk to others. A lot of other papers had to be rejected because of the risk of confounding influences.[4] Other reviews in 2020 and 2021 found that there is consistent evidence that mask-wearing is effective in reducing the spread of the SARS-CoV-2 virus[5][159] and that population-wide masking proved significant in reducing the transmission of COVID-19.[8][160]

Masks are not of equal efficacy. While N95 masks outperform surgical masks in filtration, healthcare worker population studies have not shown a significant difference between the two, as of June 2021.[8] N95 and surgical masks, both designed for single use, can be decontaminated at a loss to mask integrity and filtration efficacy.[8] Both N95 and surgical outperform cloth masks, which the general public has used based on their greater availability during mask supply shortages.[8] Cloth and fabric masks have protected wearers from COVID-19, with some variability,[9] such as fabric type, layer count, and mask fit.[161] Cloth masks are insufficient for healthcare workers and not recommended, according to two randomized controlled trials.[9] Several observational studies, including four reviewed in a 2020 Lancet meta-analysis, have found that masks offer statistically significant protection from infection, although the level of protection varies according to the mask type and setting.[63]

Clinical evidence of mask efficacy in COVID-19 transmission was limited and had become a subject of scientific debate by May 2021.[162] Clinical studies had not evaluated the efficacy of cloth masks in COVID-19 transmission by the end of 2021.[9] Evaluation of cloth mask efficacy is further complicated by the wide variation in fabric and fit, among other factors.[8] Concerning the precedent of mask efficacy in limiting transmission of respiratory viral illnesses other than COVID, a clinical trial meta-analysis in May 2021 showed no significant evidence of efficacy, though the authors noted the evidence to be poor quality and subject to confounding factors like consistent mask usage adherence.[162]

Cloth masks edit

Community studies have shown some cloth masks to be effective at filtering respiratory droplets, which can carry SARS-CoV-2.[8] Cloth masks of a cotton quilt (120 thread per inch), bonded copy paper, flannel, and a chiffon or silk hybrid with cotton are over 90% effective at blocking particles the size droplets that carry SARS-CoV-2, according to an October 2021 review of 42 studies. Multilayered fabrics provided improved breathability and filtration efficacy. Among readily available fabrics, two-layered 100% cotton, two-layered cotton quilt, hybrid masks, and cotton flannel performed best.[9] Filtration effectiveness generally improves with thread count.[8]

The use of a face mask can result in significant risk reduction of infection with epidemic-causative beta coronaviruses. N95 or similar respirators account for a larger risk reduction than disposable surgical or other similar masks.[63] Masks are protective for both healthcare workers and people in communities exposed to infection; evidence supports masking in both healthcare and non-healthcare settings, with no striking differences detected in the effectiveness of masks between the settings.[63]

The CDC highlighted a number of studies in their 10 November 2020, scientific brief detailing the benefits of community masking.[142] In a study of 124 Beijing households with at least one laboratory-confirmed case of SARS-CoV-2 infection, mask use by the index patient and family contacts before the index patient developed symptoms reduced secondary transmission within the households by 79%.[163] A retrospective case-control study from Thailand documented that, among more than 1,000 people interviewed as part of contact tracing investigations, those who reported having always worn a mask during high-risk exposures experienced a greater than 70% reduced risk of acquiring infection compared with people who did not wear masks under these circumstances.[164] A similar study in three Western countries also came up with a 70% risk reduction.[165] Investigations involving infected passengers aboard flights longer than ten hours strongly suggest that masking prevented in-flight transmissions, as demonstrated by the absence of infection developing in other passengers and crew in the 14 days following exposure.[166] In addition, the CDC said the benefit of universal masking, including reductions in infections and mortality, has been demonstrated in community-level analyses by a set of studies involving the Massachusetts hospital system, the German city Jena, the American state Arizona, a panel of 15 American states and Washington, D.C., Canada nationally, and the United States nationally.[142]

In addition to studying the impact of mask-wearing on transmission in a community, direct studies can be done on whether a mask filters out virus-carrying particles from the air. In August 2021, a study of the fabric of masks worn in the community found that they filtered out between half and three-quarters of the viral RNA.[167] Respirators made to a standard such as N95 or FFP2 when properly fitted should filter out at least 95% of the virus.

Optimal face mask designs and use edit

A scientific review of research about the overall efficacy of face masks in terms of product design (such as thermal comfort and flow resistance) and ways of usage found that fluid dynamics and fabrication techniques have a significant impact on performance. According to the review, studies showed that cotton and surgical masks had a microorganism filtration efficiency of 86.4% and 99.9% respectively, while the surgical mask was three times more effective in blocking transmission than the cotton mask and could lead to a decrease of the effective reproduction number to below 1 – which could halt epidemic spread in a region where 70% of residents use them consistently in public.[168][169]

By January 2021, several lines of research recommended double-masking (wearing a cloth mask over a surgical mask, along with using a mask filter, or wearing a nylon covering over a mask) as being efficacious.[170]

Correct handling and wearing of masks edit

A properly-worn face mask or covering covers the nose, mouth, and chin.[21][171]

As masking became widespread during the pandemic, it gave rise to the issue that many individuals of the public are not correctly handling and wearing their masks.[172][173][174] Suzanne Willard, a clinical professor at Rutgers School of Nursing, remarked that the general public is not used to wearing masks and lay people are asked to use a tool health care professionals are trained to use.[175]

A commonly seen issue is that people are wearing masks pulled down below the nose, which is an incorrect way to wear a mask.[176][177] Zane Saul, the chief of infectious disease at Bridgeport Hospital, remarked that "I really have observed people not covering their noses and just covering their mouths. It's just as important to cover your nose."[176] Daniel Gottschall, the vice president of medical affairs for the Fairfield region of Hartford HealthCare and St. Vincent's Medical Center in Bridgeport, explained that "By wearing a mask you're keeping a lot of those secretions inside of you. If you wear it just over your nose or just over your mouth and you're not diligent (about keeping it in place), you're exposing the secretions that come out of that part of the body to other people."[176]

A face mask is carefully taken off by handling the ties or loops without touching the front.[21][171]

Zeynep Tufekci, a professor of information science, remarked that messaging on masking should have been used to provide proper instructions to the public (as was done for hand washing) rather than used to discourage people from masking because of the possibility that they would wear them improperly, as had happened early in the pandemic.[83] The European Centre for Disease Prevention and Control highlighted that the appropriate use of face masks in communities could be improved through education campaigns and is key for its effectiveness as a measure.[73] Health institutions such as the World Health Organization have provided public guidance on the do's and don'ts on masking.[21]

Shortages of face masks edit

Early epidemic in mainland China edit

As the epidemic accelerated, the mainland market in China saw a shortage of face masks due to increased public demand.[178] Face masks were quickly sold out in stores throughout China.[179] Hoarding and price gouging drove up prices, so the market regulator said it would crack down on such acts.[180][181] In January 2020, price controls were imposed on all face masks on Taobao and Tmall.[182] Other Chinese e-commerce platforms – JD.com,[183] Suning.com,[184] Pinduoduo[185] – did likewise; third-party vendors would be subject to price caps, with violators subject to sanctions.[citation needed]

By March, China had quadrupled its production capacity to a hundred million masks per day.[140]

National stocks and shortages edit

At the beginning of the COVID-19 outbreak in the United States, the U.S.'s Strategic National Stockpile contained just twelve million N95 respirators, far fewer than estimates of the amount required.[186] Millions of N95s and other supplies were purchased from 2005 to 2007 using congressional supplemental funding, but 85 million N95s were distributed to combat the 2009 swine flu pandemic, and Congress did not make the necessary appropriations to replenish stocks.[186] The Stockpile's primary focus has also primarily been on biodefense (defense against a terrorist or weapon of mass destruction attack) and response to natural disaster, with the infectious disease a secondary focus.[186] By 1 April 2020, the Stockpile was nearly emptied of protective gear.[187] In January and February 2020, U.S. manufacturers, with the encouragement of the Trump administration, shipped millions of face masks and other personal protective equipment to the PRC, a decision that subsequently prompted criticism given the mask shortage that the U.S. faced during the pandemic.[188]

In France, 2009 H1N1-related spending rose to €382 million, mainly on supplies and vaccines, which was later criticized.[189][190] It was decided in 2011 to not replenish its stocks and rely more on supply from China and just-in-time logistics.[189] In 2010, its stock included a billion surgical masks and 600 million FFP2 masks; in early 2020, it was 150 million and zero respectively.[189] While stocks were progressively reduced, a 2013 rationale stated the aim to reduce costs of acquisition and storage, now distributing this effort to all private enterprises as an optional best practice to ensure their workers' protection.[189] This was especially relevant to FFP2 masks, more costly to acquire and store.[189][191] As the COVID-19 pandemic in France took an increasing toll on medical supplies, masks and PPE supplies ran low, causing national outrage. France needed forty million masks per week, according to French president Emmanuel Macron.[192] France instructed its few remaining mask-producing factories to work 24/7 shifts and to ramp up national production to forty million masks per month.[192] French lawmakers opened an inquiry on the past management of these strategic stocks.[193] The mask shortage has been called a "scandal d'État" (State scandal).[194] Thousands of French individuals and companies teamed up during the outbreak to form a decentralized network of Fab labs and ad-hoc retooled production facilities, producing more than a million face shields, masks and other kinds of PPE during the height of the pandemic.[195]

In late March and early April 2020, as Western countries were, in turn, dependent on China for supplies of masks and other equipment, China was seen as making a soft-power play to influence world opinion.[196][197] However, a batch of masks purchased by the Netherlands was rejected as being sub-standard. The Dutch health ministry issued a recall of 600,000 face masks from a Chinese supplier on 21 March which did not fit properly and whose filters did not work as intended despite them having a quality certificate.[196][197] The Chinese Ministry of Foreign Affairs responded that the customer should "double-check the instructions to make sure that you ordered, paid for, and distributed the right ones. Do not use non-surgical masks for surgical purposes."[197] Eight million of eleven million masks delivered to Canada in May also failed to meet standards.[198][199]

Theft edit

Thefts of face masks and other personal protective equipment have been reported at hospitals in the United States and other countries.[200] The Naval Medical Center San Diego began mandatory random bag checks for staff members, after several incidents of theft.[201] Hospitals in Canada reported that theft of PPE had become so commonplace that face masks had to be locked away. According to hospital staff, the policy of locking up PPE often resulted in staff requests for PPE being denied.[202] Thefts of N95 masks were reported from a locked hospital office in South Carolina and off-loading docks at the University of Washington.[203]

Two thousand surgical masks were stolen from a hospital in Marseille, France, during the early months of the COVID-19 outbreak, in March. The masks were stolen from an area of the hospital that could only be accessed by surgery patients and staff.[204] A hospital employee in Cooperstown, New York, was charged with misdemeanor larceny for a similar incident.[205] Hospital employees in West Java, Indonesia, were arrested for stealing hundreds of boxes of face masks and selling them on the black market.[206]

One month later an Indiana hospital pharmacy reported a theft to the Drug Enforcement Administration. Along with morphine, with a street value estimated at $3000, the thieves, one of whom was an employee of the hospital and had an access card, had stolen masks and other in-demand goods. In the criminal complaint, filed in Indiana federal court, a DEA task force officer said:[200]

Based on my training and experience, I know these items are highly sought after in the secondary market due to shortages resulting from the Coronavirus pandemic and that these types of items are being sold on the secondary market at an increased price well over fair market value.

A former hospital employee in Georgia was arrested on allegations of stealing masks and gloves from the hospital on five separate occasions after he was fired.[207] Also in April, an employee of the Charlie Norwood VA Medical Center was charged with a misdemeanor for stealing disposable gowns and surgical masks from the hospital.[208] PPE, including masks, were reported stolen by a member of the housekeeping staff at a hospital in Arizona and a physician's assistant in Florida.[209][210]

According to a BBC News report from August 2020, hospital staff in Ghana were selling PPE on the black market.[211]

Two government workers from the Federal Law Enforcement Training Center in North Charleston, South Carolina, were charged in October for conspiracy to steal PPE, obstruction of justice and lying to the FBI.[212]

N95 and FFP masks edit

N95 and FFP masks were in short supply and high demand during the COVID-19 pandemic.[213][189] Production of N95 masks was limited due to constraints on the supply of nonwoven polypropylene fabric (which is used as the primary filter), as well as the cessation of exports from China.[51][214] China controls fifty percent of global production of masks, and facing its own coronavirus epidemic, dedicated all its production for domestic use, only allowing exports through government-allocated humanitarian assistance.[51]

United States edit

In March 2020, US President Donald Trump applied the Defense Production Act against the American company 3M, which allows the Federal Emergency Management Agency to obtain N95 respirators from 3M.[215][216] White House trade adviser Peter Navarro said there were concerns that 3M products were not making their way to the US.[215] 3M replied that it has not changed the prices it charges, and was unable to control the prices its dealers or retailers charge.[215]

Jared Moskowitz, the head of the Florida Division of Emergency Management, accused 3M of selling N95 masks directly to foreign countries for cash, instead of to the US. Moskowitz said 3M agreed to authorize distributors and brokers to represent they were selling the masks to Florida, but instead his team for the last several weeks "get to warehouses that are completely empty". He then said the 3M-authorized US distributors later told him the masks Florida contracted for never showed up because the company instead prioritized orders that came in later, for higher prices, from foreign countries (including Germany, Russia, and France).[217][218][219]

Forbes reported that "roughly 280 million masks from warehouses around the US had been purchased by foreign buyers [on 30 March 2020] and were earmarked to leave the country, according to the broker – and that was in one day", causing massive critical shortages of masks in the US.[220][221]

Masks were still in short supply in late September, eight months into the pandemic. The Defense Production Act powers that averted a ventilator shortage were not used as extensively to increase N95 production, despite outcry from healthcare workers. Even though 3M has increased domestic production from 20 million to 95 million masks a month, they say "the demand is more than we, and the entire industry, can supply for the foreseeable future."[222][223] N95 manufacturers and other companies have been reluctant to invest more in domestic mask production because manufacturing in the United States is not profitable for them. There are some American companies who can shift production temporarily to meet the demand for masks but most of them have not received any funding through the DPA. Some have taken the initiative but there were problems with the fit of the masks and obtaining regulatory approvals. 3M and other N95 manufacturers have not entered into any corporate partnerships to share intellectual property or increase N95 production.[222]

Trump gave Rear Admiral John Polowczyk the responsibility for PPE logistics. Polowczyk said he believed "hospital systems are making management decisions that might lead to an appearance that we still don't have masks, which is the farthest from the truth."[222]

By February 2021, suppliers had increased production but not enough to meet demand. Companies cited concerns about post-pandemic demand as a reason for not entering the market. Hospitals increased supplies, but even at well-funded hospitals, healthcare workers could be expected to wear their masks for up to a month. Counterfeits continued to pose problems for purchasers.[224] Numerous calls by public health experts had been made to provide high-filtration masks such as N95s or their equivalents to the general public in high-risk settings.[225][226]

On 19 January 2022, the Biden administration is reported to begin freely providing 400 million N95 masks in the United States.[227]

Germany edit

In early April 2020, the Berlin politician Andreas Geisel alleged that a shipment of 200,000 N95 masks it had ordered from American producer 3M's China facility was intercepted in Bangkok, Thailand, and diverted to the United States. 3M said they had no knowledge of the shipment, stating "We know nothing of an order from the Berlin police for 3M masks that come from China." The US government denied any confiscation and said they use appropriate channels for all their purchases.[228][229] Berlin police later confirmed that the shipment was not seized by US authorities.[citation needed]

This revelation outraged the Berlin opposition, whose CDU parliamentary group leader Burkard Dregger accused Geisel of "deliberately misleading Berliners" in order "to cover up its own inability to obtain protective equipment". FDP interior expert Marcel Luthe also criticized Geisel.[230] Politico Europe reported that "the Berliners are taking a page straight out of the Trump playbook and not letting facts get in the way of a good story."[231] The Guardian also reported that "There is no solid proof Trump [nor any other American official] approved the [German] heist."[232]

German citizens decided to contribute to solving the supply crisis by making their own masks and other types of PPE like face shields that gave masks additional protection; the largest group of makers measured 6,800 individuals, collectively producing more than 100,000 pieces of protective equipment.[233]

Canada edit

As more countries restricted the export of N95 masks, Novo Textiles in British Columbia announced plans to start producing N95 masks in Canada.[234] AMD Medicom in Quebec had long been the main Canadian company producing N95s, but China, France, the Republic of China (Taiwan) and the United States all banned exports of medical equipment, barring Medicom's factories there from exporting the masks to Canada. The Government of Canada subsequently awarded Medicom a 10-year contract to build a factory to produce masks in Montreal.[235]

Mask industry edit

Manufacturing edit

Masks being produced in Taiwan

China edit

As of 2019, mainland China manufactured half the world's output of masks.[236] As COVID-19 spread, enterprises in several countries quickly started or increased the production of face masks.[237] Cottage industries and volunteer groups also emerged, manufacturing cloth masks for localized use. They used various patterns, including some with a bend-to-fit nosepiece insert. Individual hospitals developed and requested a library of specific patterns.[238][239][240][241]

In the first five months of 2020, 70,802 new companies registered in China to make or trade face masks, a 1,256% increase compared to 2019, and 7,296 new companies registered to make or trade melt blown fabrics, a key component of face masks, a 2,277% rise from 2019.[242]

In April, however, the Chinese government stepped in with tighter regulations. 867 producers of the melt-blown fabric were shut down in Yangzhong city alone. Many speculative manufacturers have been forced to quit due to changing export rules and tighter licensing requirements in China and weaker demand for lower quality products globally.[242]

Open-Source and Do-It-Yourself Masks edit

Open Source Medical Supplies coordinated and shared open-source mask designs.[243]

Distribution edit

Some clinical stockpiles have proved inadequate in scale, and the non-medical market demand expanded dramatically as the general public determined that masks were essential, or they began obeying public health mandates, or both.[244]

Between April and June 2020, sellers on Etsy sold 29 million cloth face masks worth an estimated $364 million. Approximately four million people (about seven percent of buyers) visited the website just to buy masks.[245]

Society and culture edit

Attitudes edit

In mid-2020 as the pandemic grew, the public interest in face masks as a means of protection was greatly increased,[246] often even before governments implemented mandatory mask-wearing.[247]

In East Asian societies, a primary reason for mask-wearing is to protect others from oneself.[248][249] The broad assumption behind the act is that anyone, including seemingly healthy people, can be a carrier of the coronavirus.[249] The usage of masks is seen as a collective responsibility to reduce the transmission of the virus.[250] A face mask is thus seen as a symbol of solidarity in Eastern countries.[250] Elsewhere, the need for mask-wearing is still often seen from an individual perspective where masks only serve to protect oneself.[248] In April 2020, a study comparing masking-related perceptions between China and three German speaking countries (Austria, Germany, and Switzerland) also showed that Chinese had stronger pro-masking perceptions than the European participants.[251] However, in 2020, people began promoting a new meaning of masking as an act of solidarity to each other.[252][141][253][254]

Slovakia was one of the first countries in the world to introduce universal masking in public places.[255]

Existing cultural norms and social pressure may impede mask-wearing in public, which may explain why masking was initially avoided in the West.[256] According to Joseph Tsang, a Hong Kong doctor, and infectious disease expert, the promotion of universal masking may resolve perceptions against mask-wearing because mask-wearing is intimidating if few people wear masks due to cultural barriers, but if all people wear masks it shows a message that people are in this together.[82] A May 2020 study surveying people in Spain showed that an individual's likelihood of voluntarily wearing a mask is positively correlated with the proportion of uptake in the surrounding area.[257]

Helene-Mari van der Westhuizen et al. state that successful implementation of public masking policies, especially in communities that have no cultural traditions for such interventions, requires a reframing of social meanings and moral worth, and that public messages help to conceptualize who typically wear masks and what the moral valence of masking is.[258] They note that the earliest members who wear face coverings may be seen as deviant when the community starts to adopt masking, but that changing narratives will generate new meanings that construe those who do not mask as deviant.[258] Their argument is that public health messaging about face coverings should shift from masks as a medical intervention to masks as a social practice based on values such as social responsibility and solidarity, as a successful uptake requires face coverings to be grounded in the social and cultural realities of affected communities.[258] Clemens Eisenmann and Christian Meyer argue that the question, how the meaning of wearing face masks develops in society, depends on their practical and public uses within everyday social interactions.[259] They explain that masking has destabilized interactional infrastructures embedded in routines, revealing both taken-for-granted infrastructures of everyday life – including social inequalities (such as those of people reliant on lip reading) and moral evaluations in transcultural situations (such as those involving implicit racism in which the health instructions of essential workers belonging to certain groups are disregarded) – and new challenges on the interactional level.[259]

In the Western world, as of 2020 the public usage of masks still often carried a large stigma,[248][250][260] being seen as a sign of sickness.[260] This stigmatization is a large obstacle to overcome, because people may feel too ashamed to wear a mask in public and therefore opt to not wear one.[261] There is also a divide within the Western world, as seen in the Czech Republic and Slovakia where mass mobilization has occurred to reinforce the solidarity in mask-wearing since March 2020.[248][needs update]

Mask-wearing has been called a prosocial behavior in which one protects others within their community.[262][263][264] On social media, there has been an effort with the #masks4all campaign to encourage people to use masks.[265] Nevertheless, there have been many occurrences of violence and hostility by people who became aggressive after they were requested to wear a mask or saw people wearing masks in customer-based establishments.[266][267][268][269] Multiple people have been killed in attacks by people who refused to wear masks.[270] It has led to concerns about worker safety, so employees have been discouraged to actively enforce masking policies due to the potential of hostile situations, while enforcement by official authorities is severely lacking.[271]

Masking has been subjected to racial politics in Western countries.[272] For instance, in 2020 it had been heavily racialized as an Asian phenomenon.[250][259] This had been reinforced in a lot of media discourses, where stories about the pandemic were often accompanied by unrelated imagery of Asian people in masks.[272][273] The focus on race brought hostility towards Asians who are confronted with the choice to wear masks as a precaution while they face discrimination for it.[272][274] Huang Yinxiang, a sociologist from the University of Manchester, described maskaphobia (negative prejudice, fear or bitter hatred against people wearing face masks) as making Asians in Western countries into targets for racists who want to legitimize xenophobia during the COVID-19 outbreak.[275] Likewise, people from certain groups such as Black Americans may not feel comfortable wearing masks, especially those that are not clearly medical but homemade masks, due to concerns of racial profiling.[276][277][278]

A sign language interpreter (on the right) in Hong Kong is wearing a transparent mask to allow lip reading.

There have also been concerns that wearing masks may also further isolate disadvantaged communities. Concerns had been expressed that masks would make communication difficult for people who are deaf or hard-of-hearing.[279][280][281][282][283] This led to calls for wider distributions of transparent masks, which allow for lip reading.[279][280][284]

Similar concerns over difficulty in communicating have been expressed by those who may depend on dogs for therapeutic or social reasons, as the animals depend on body language such as facial expressions.[285] Conversely, people who are exempt from wearing masks on medical grounds or due to a disability, fear they will be subjected to abuse for not wearing a mask, even if they are legally exempt from doing so.[286] For instance, in the United Kingdom, the charity Disability Rights UK received numerous reports about people being confronted on trains and buses.[286] Health organizations such as the American Lung Association commented that, even though there may be people who will seek an exemption, the individual's concerns needs to be weighed against the societal needs to limit the spread of the virus.[287][288] However, anti-maskers have called upon bogus claims about legal or medical exemptions in their refusal to wear masks.[287] They have, for instance, claimed that the Americans with Disabilities Act (designed to prohibit discrimination based on disabilities) allows exemption from mask requirements, but the United States Department of Justice responded that the act "does not provide a blanket exemption to people with disabilities from complying with legitimate safety requirements necessary for safe operations".[289]

There have been concerns about the effects of mask-wearing on young children's language development and social emotional development.[290][291][292][293][294] It has been argued that mask mandates for children may have taken insufficient consideration of children's human rights.[295]

In November 2020, there were feelings of mask fatigue among the general public, exacerbated by frustrations about people who are not taking the mask and other guidelines seriously as the pandemic and its intensity continued on.[296]

Trends edit

Two Indian boys sporting face mask at a public event

Among the European countries surveyed by YouGov in the first half of 2020, the likelihood for people to wear masks was split: In Northern Europe (e.g., Finland, Sweden, Norway, and Denmark), people were very unlikely to wear a mask.[297] In Western Europe (e.g., Italy, Spain, France, and Germany), people were initially unlikely to use a mask, but mask wearing greatly changed from low levels in March to higher levels in May.[297] A similar, if delayed, pattern was seen in some northern European countries. For example, mask usage was very low in Denmark up until the summer of 2020 but rapidly increased in the autumn as rules on their use in publicly accessible indoor places were introduced.[298] An exception was the United Kingdom where mask usage only grew gradually in the first half of 2020,[297] but it rose very quickly after official policy changes in July mandated masking in stores.[299] In May 2020, masking was gradually shifting to become a new social norm.[300]

A survey among people from the United States (conducted from April to June 2020) indicates that age was a factor in whether people were likely to wear a mask, as the likelihood rose with the age group, but the reported use of face masks increased significantly across all age groups over time.[301] Furthermore, people who did not report mask use also reported engaging in significantly fewer other mitigation behaviors than those who did report mask use.[301]

In 2020, gender played a role in the willingness to wear masks; men were overall less inclined to wear masks in public than women.[302][303][304] There were indications that men were more likely to feel negative emotions (such as shame) and stigma for wearing masks.[302][303] It was suggested that this male behavior is driven by a sense of masculinity, where the act of masking is possibly perceived to run counter to it, which led to an increase in men not wearing masks.[305][306] A 2020 survey among participants recruited from Amazon Mechanical Turk about face mask perceptions found that men and women may have different reasons when they do not wear masks in public: Men were more likely to see masks as an infringement upon their independence and women were more likely to perceive masks as being uncomfortable, while perceptions on efficacy, accessibility, compensation, inconvenience, appearance, and attention did not differ.[307]

By 2023, most jurisdictions had ended their mask mandates.[7] By May 2023, people in most countries largely stopped wearing masks.[308]

Governmental role edit

The heads of state and government of Portugal and Spain wearing face masks during an official ceremony in July 2020

The pandemic has raised questions about the role of governments in mask policies, either voluntary or mandatory policies, especially in terms of the social and behavioral consequences involving the general public.[264]

The results from a study surveying people in Germany indicate that the act of wearing a mask, independent of the policy, is considered a social contract in which compliant people perceive each other more positively and noncompliance is negatively evaluated.[264] However, it also suggests that voluntary policies have the potential effect to increase polarization and thus cause more stigmatization.[264] The authors recommended that countries and communities should adopt a mandatory policy along with explicit communication of the benefits of both masking (e.g., risk reduction, mutual protection, positive social signaling) and mandatory policies (e.g., fairness, less stigmatization, higher effectiveness) to encourage the public to wear masks.[264]

World leaders as role models for masking have also received much scrutiny, as they are key to convey the critical public health message to the public.[309][310] For example, Slovakia has been cited as a country where its public figures (including President Zuzana Čaputová and her administration) set the example by wearing masks and played a crucial role to normalize masks.[311] In contrast, in the United States, President Donald Trump and his administration came under criticism for communicating an inconsistent and confusing message about masking.[312][313] They were often criticized for undercutting national and local public health advice to wear masks.[314][315]

Politics edit

U.S. Surgeon General Jerome Adams urged people to wear face masks and acknowledged that it is difficult to correct earlier messaging that masks do not work for the general public.[316]

Although authorities, especially in Asia, have been recommending people to wear face masks in public, in many other parts of the world, conflicting advice has caused much confusion among the general population.[317] Several governments and institutions, such as in the United States, initially dismissed the use of face masks by the general population, often with misleading or incomplete information about the usefulness of masks.[318][319][320] Commentators have attributed the anti-mask messaging to efforts to manage the mask shortages, as governments did not act quickly enough, remarking that the claims go beyond the science or were simply lies.[320][321][322][323] On 12 June 2020, Anthony Fauci, a key member of the White House coronavirus task force, confirmed that the American public were not told to wear masks from the beginning due to the shortages of masks and explained that masks do actually work.[324][325][326][327][328][excessive citations]

In the United States, public masking has become a political issue, as opponents argue that it inhibits personal freedom and proponents emphasize the importance of masks for public health.[329] Some people may see it as a political statement.[330] Party affiliation partly determined how likely people were to embrace the wearing of masks in public.[330][331] Democrats were more likely to wear masks than Republicans.[330][331] Masks have become an aspect of the culture war that has emerged over the course of the pandemic.[329][330][331] Commentators argue that the resistance against masks partly stems from the confusing and mixed messaging about masking.[329][332][333]

Matthew Facciani, a sociologist at Vanderbilt University, says the uncertainty from health experts during the early days of the pandemic paved the way for political leaders to become a prominent source of guidance and clarity.[334] He argues that once mask-wearing became informed by political beliefs, it is difficult to correct due to the motivation to protect one's identity in relation to a political group and the reinforcement from political echo chambers, no matter that scientists began to better understand the severity of the virus and the evidence in favor for mask wearing became clearer.[334] Moreover, how people observe the masking rules seems to be different across countries and these differences may be attributed to cultural or management factors.[251]

In April 2020, health officials from Taiwan's Central Epidemic Command Center (CECC) pushed back on school bullying of boys in pink face masks.[335] The CECC officials and Minister of Health and Welfare Chen Shih-chung wore pink masks to challenge gender norms at a press conference, while various government agencies demonstrated solidarity by changing the colors on their Facebook pages to pink.[335] The minister later tweeted "Pink is for everyone and no color is exclusive for girls or boys. Gender Equality lies at the heart of Taiwan values."[335] The press conference was held amid reports that male students were too embarrassed to wear their pink face masks, jeopardizing their safety and the safety of others in the face of COVID-19.[335]

Opposition edit

"Masks Don't Work", a protest placard in Ohio, United States, during the COVID-19 pandemic in May 2020.

In some countries, large rallies took place in protest against masking mandates.[336][337][338] In Canada, opponents of masking hailed their protests as the "March to Unmask".[338][339] In the United Kingdom, new protests came in the wake of the official announcement that masking will be compulsory in shops.[336] After eight months since the beginning of the lockdown in the Czech Republic, mass manifestations against the restrictions imposed by the government arose.[340][341] Some anti-mask protestors co-opted the feminist slogan "my body, my choice"[342][343][344] and the Black Lives Matter slogan "I can't breathe".[345] Businesses were also purposely disrupted by anti-maskers (purportedly in defense of their constitutional rights).[346]

In the United States, opposition to mask-wearing during the COVID-19 pandemic came during then-President Donald Trump's politicization of science[347] and more generally during decades-old period of politicization of science. American opposition to mask-wearing during pandemics is not new; during the 1918 influenza pandemic, the Anti-Mask League was established in San Francisco, California.[348]

In May 2021, Vice reported that some members of the anti-vaccine community were promoting the use of masks and social distancing to protect themselves from those who have received vaccines, citing false claims that those vaccinated for COVID-19 "shed" spike proteins that can be harmful to people in their proximity, and former research scientist Judy Mikovits claimed that she had been kicked off a plane for wearing a mask lined with colloidal silver.[349]

Attractiveness edit

Face masks are sometimes deemed to make people look more attractive. This may be because they hide unattractive features or are associated with medical personnel.[350]

Religion edit

In 2020, Christian clergy from the Lutheran, Catholic, Presbyterian, Anglican, Baptist, and Latter-day Saint traditions, as well as those from the Jewish, Buddhist, and Unitarian religions, implored people to wear masks.[351]

Fashion edit

A cloth face mask matching the rest of the ensemble

As the pandemic progressed people began making use of face masks as accessories,[352][353][354][355] matching them to their outfits and so on.[356][357] Early in the pandemic, people and businesses from the fashion industry responded to official calls for help in overcoming the shortages of protective personal equipment including face masks.[358] These masks were sheerly utilitarian as the only consideration at the time was function.[359] What began as a public health necessity however gradually evolved into a new category of accessories subject to similar design and marketing considerations as other accessories.[360] Fashion brands eventually reopened their factories for production due to the increasing demand for masks and started to manufacture masks in a wider variety of styles.[353] Smaller brands, who primarily sold their products online, found that selling masks was a good strategy to maintain sales.[361] Etsy became a major online platform where many designers sold their masks.[361] Designers started making masks that matched other pieces of clothing and accessories,[362][363] a trend which may have begun unintentionally as even fabric remnants were repurposed.[363]

The city of Vilnius in Lithuania held a "Mask Fashion Week" in May 2020, which was promoted with billboards (with no catwalks or displays) around the city featuring local people including Mayor Remigijus Simasius wearing face masks.[364]

The Walt Disney Company introduced uniform face masks for their employees at Walt Disney World and Disneyland in the United States.[365][366]

Environment edit

Large numbers of disposed face masks have led to an increase in plastic waste, negatively impacting the environment.[367][368][369] Moreover, the production of face masks also contributes the emission of carbon dioxide, which accelerates global warming.[370] Considering the risk of plastic pollution, researchers have focused on using biodegradable polymers to fabricate facemask with antimicrobial properties[371]

Terminology edit

Due to the rarity of their use in non-medical settings outside East Asia, many languages lacked commonly used terms for facemasks, especially since legal issues prevent the usage of terms which might imply medical standards the masks do not meet.[372] In languages such as Saterland Frisian public competitions were held[373] to create a neologism for the device in the language and thus not having to rely on loanwords or calques.[374][375] The Friisk Foriining [frr] held a similar competition for the North Frisian language.[376][377]

See also edit

Notes edit

  1. ^ Knot and tuck technique: Modification to ear loop masks where the top and bottom of the ear loop string are knotted together at the mask's edges and extra material is tucked in towards the face.[44]

References edit

  1. ^ a b Bourouiba L (July 2021). "Fluid Dynamics of Respiratory Infectious Diseases". Annual Review of Biomedical Engineering. 23 (1): 547–577. doi:10.1146/annurev-bioeng-111820-025044. hdl:1721.1/131115. PMID 34255991. S2CID 235823756.
  2. ^ a b Matuschek C, Moll F, Fangerau H, Fischer JC, Zänker K, van Griensven M, et al. (August 2020). "Face masks: benefits and risks during the COVID-19 crisis". European Journal of Medical Research. 25 (1): 32. doi:10.1186/s40001-020-00430-5. PMC 7422455. PMID 32787926.
  3. ^ a b Catching A, Capponi S, Yeh MT, Bianco S, Andino R (August 2021). "Examining the interplay between face mask usage, asymptomatic transmission, and social distancing on the spread of COVID-19". Scientific Reports. 11 (1). Nature Portfolio: 15998. Bibcode:2021NatSR..1115998C. doi:10.1038/s41598-021-94960-5. PMC 8346500. PMID 34362936. S2CID 236947786. Masks prevent the spread of droplets and aerosols generated by an infected individual, and when correctly worn surgical masks can reduce viral transmission by 95%. Uninfected individuals wearing a surgical mask are about 85% protected against infection.
  4. ^ a b c d Talic S, Shah S, Wild H, Gasevic D, Maharaj A, Ademi Z, et al. (November 2021). "Effectiveness of public health measures in reducing the incidence of covid-19, SARS-CoV-2 transmission, and covid-19 mortality: systematic review and meta-analysis". BMJ. 375: e068302. doi:10.1136/bmj-2021-068302. PMC 9423125. PMID 34789505. S2CID 244271780. The results of additional studies that assessed mask wearing ... indicate a reduction in covid-19 incidence, SARS-CoV-2 transmission, and covid-19 mortality. Specifically, a natural experiment across 200 countries showed 45.7% fewer covid-19 related mortality in countries where mask-wearing was mandatory. Another natural experiment study in the US reported a 29% reduction in SARS-CoV-2 transmission (measured as the time-varying reproductive number Rt) (risk ratio 0.71, 95% confidence interval 0.58 to 0.75) in states where mask-wearing was mandatory. A comparative study in the Hong Kong Special Administrative Region reported a statistically significantly lower cumulative incidence of covid-19 associated with mask-wearing than in selected countries where mask-wearing was not mandatory.
  5. ^ a b c "Science Brief: Community Use of Masks to Control the Spread of SARS-CoV-2". CDC. 11 February 2020. Experimental and epidemiologic data support community masking to reduce the spread of SARS-CoV-2, including alpha and delta variants, among adults and children. [...] Mask use has been found to be safe and is not associated with clinically significant impacts on respiration or gas exchange under most circumstances, except for intense exercise. The limited available data indicate no clear evidence that masking impairs emotional or language development in children. [I]n combination with other contextual cues, masks are unlikely to produce serious impairments of children's social interactions. A study of 2-year-old children concluded that they were able to recognize familiar words presented without a mask and when hearing words through opaque masks. Among children with autism spectrum disorders (ASD), interventions including positive reinforcement and coaching caregivers to teach mask-wearing have improved participants' ability to wear a face mask. These findings suggest that even children who may have difficulty wearing a mask can do so effectively through targeted interventions.
  6. ^ a b Jefferson T, Dooley L, Ferroni E, Al-Ansary LA, van Driel ML, Bawazeer GA, et al. (January 2023). "Physical interventions to interrupt or reduce the spread of respiratory viruses". The Cochrane Database of Systematic Reviews. 1 (1): CD006207. doi:10.1002/14651858.CD006207.pub6. PMC 9885521. PMID 36715243.
  7. ^ a b c d Boulos L, Curran JA, Gallant A, Wong H, Johnson C, Delahunty-Pike A, et al. (2023). "Effectiveness of face masks for reducing transmission of SARS-CoV-2: A rapid systematic review". Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences. 381 (2257). Bibcode:2023RSPTA.38130133B. doi:10.1098/rsta.2023.0133. PMC 10446908. PMID 37611625.
  8. ^ a b c d e f g h i Ju JT, Boisvert LN, Zuo YY (June 2021). "Face masks against COVID-19: Standards, efficacy, testing and decontamination methods". Advances in Colloid and Interface Science. 292: 102435. doi:10.1016/j.cis.2021.102435. PMC 8084286. PMID 33971389.
  9. ^ a b c d e f g Ataei M, Shirazi FM, Nakhaee S, Abdollahi M, Mehrpour O (October 2021). "Assessment of cloth masks ability to limit Covid-19 particles spread: a systematic review". Environmental Science and Pollution Research International. 29 (2): 1645–1676. doi:10.1007/s11356-021-16847-2. PMC 8541808. PMID 34689269.
  10. ^ Center for Devices and Radiological Health (15 September 2021). "N95 Respirators, Surgical Masks, Face Masks, and Barrier Face Coverings". FDA.
  11. ^ CDC (11 February 2020). "Considerations for Wearing Masks". Centers for Disease Control and Prevention. Retrieved 25 January 2021.
  12. ^ Deepthi R, Masthi NR, Nirmala CJ, Manjula R, Vinothkumar S (20 April 2020). "Personal Protective Equipments (PPE) – Prerequisites, Rationale, and Challenges during COVID 19 Pandemic". Indian Journal of Community Health. 32 (2 (Supp)): 196–205. doi:10.47203/IJCH.2020.v32i02SUPP.005. S2CID 225952423.
  13. ^ Lam SC, Suen LK, Cheung TC (August 2020). "Global risk to the community and clinical setting: Flocking of fake masks and protective gears during the COVID-19 pandemic". American Journal of Infection Control. 48 (8): 964–965. doi:10.1016/j.ajic.2020.05.008. PMC 7219383. PMID 32405127.
  14. ^ Sankhyan S, Heinselman KN, Ciesielski PN, Barnes T, Himmel ME, Teed H, et al. (2021). "Filtration Performance of Layering Masks and Face Coverings and the Reusability of Cotton Masks after Repeated Washing and Drying". Aerosol and Air Quality Research. 21 (11): 210117. doi:10.4209/aaqr.210117. ISSN 2071-1409. S2CID 237538485.
  15. ^ a b Zangmeister CD, Radney JG, Vicenzi EP, Weaver JL (July 2020). "Filtration Efficiencies of Nanoscale Aerosol by Cloth Mask Materials Used to Slow the Spread of SARS-CoV-2". ACS Nano. 14 (7): 9188–9200. doi:10.1021/acsnano.0c05025. PMC 7341689. PMID 32584542.
  16. ^ a b c d e f g h Garcia Godoy LR, Jones AE, Anderson TN, Fisher CL, Seeley KM, Beeson EA, et al. (May 2020). "Facial protection for healthcare workers during pandemics: a scoping review". BMJ Global Health. 5 (5): e002553. doi:10.1136/bmjgh-2020-002553. PMC 7228486. PMID 32371574.
  17. ^ Konda A, Prakash A, Moss GA, Schmoldt M, Grant GD, Guha S (May 2020). "Aerosol Filtration Efficiency of Common Fabrics Used in Respiratory Cloth Masks". ACS Nano. 14 (5): 6339–6347. doi:10.1021/acsnano.0c03252. PMC 7185834. PMID 32329337.
  18. ^ Daoud AK, Hall JK, Petrick H, Strong A, Piggott C (1 January 2021). "The Potential for Cloth Masks to Protect Health Care Clinicians From SARS-CoV-2: A Rapid Review". Annals of Family Medicine. 19 (1): 55–62. doi:10.1370/afm.2640. PMC 7800735. PMID 33431393.
  19. ^ Davies A, Thompson KA, Giri K, Kafatos G, Walker J, Bennett A (August 2013). "Testing the efficacy of homemade masks: would they protect in an influenza pandemic?". Disaster Medicine and Public Health Preparedness. 7 (4): 413–418. doi:10.1017/dmp.2013.43. PMC 7108646. PMID 24229526.
  20. ^ Aydin O, Emon B, Cheng S, Hong L, Chamorro LP, Saif MT (October 2020). "Performance of fabrics for home-made masks against the spread of COVID-19 through droplets: A quantitative mechanistic study". Extreme Mechanics Letters. 40: 100924. Bibcode:2020ExML...4000924A. doi:10.1016/j.eml.2020.100924. PMC 7417273. PMID 32835043.
  21. ^ a b c d e "Coronavirus disease (COVID-19) advice for the public: When and how to use masks". World Health Organization. 20 October 2020. Archived from the original on 29 October 2020.
  22. ^ a b Clase CM, Fu EL, Ashur A, Beale RC, Clase IA, Dolovich MB, et al. (October 2020). "Forgotten Technology in the COVID-19 Pandemic: Filtration Properties of Cloth and Cloth Masks-A Narrative Review". Mayo Clinic Proceedings. 95 (10): 2204–2224. doi:10.1016/j.mayocp.2020.07.020. PMC 7834536. PMID 33012350.
  23. ^ Clase CM, Fu EL, Ashur A, Beale RC, Clase IA, Dolovich MB, et al. (October 2020). "Forgotten Technology in the COVID-19 Pandemic: Filtration Properties of Cloth and Cloth Masks-A Narrative Review". Mayo Clinic Proceedings. 95 (10): 2204–2224. doi:10.1016/j.mayocp.2020.07.020. PMC 7834536. PMID 33012350.
  24. ^ "Frequent Questions About Hand Hygiene: Handwashing". Centres for Disease Control and Prevention. 14 October 2020. Retrieved 7 November 2020.
  25. ^ "How to Safely Wear and Take Off a Cloth Face Covering" (PDF). CDC.
  26. ^ "Does a PM 2.5 filter help with coronavirus? - UAB Medicine News - UAB Medicine". uabmedicine.org. Retrieved 7 November 2020.
  27. ^ a b "EPA Researchers Test Effectiveness of Face Masks, Disinfection Methods Against COVID-19". 5 April 2021.
  28. ^ a b c "N95 Respirators and Surgical Masks (Face Masks)". U.S. Food and Drug Administration. 11 March 2020. Retrieved 28 March 2020.   This article incorporates text from this source, which is in the public domain.
  29. ^ "COVID-19 Q&A with Dr. Roy Kirkpatrick: Wearing masks". Huntsville Doppler. 21 May 2020. Archived from the original on 13 March 2022. Retrieved 13 March 2022.
  30. ^ Wei NK (6 May 2019). "What is PM0.3 and Why Is It Important?". Smart Air Filters.
  31. ^ US 5496507, "Method Of Charging Electret Filter Media" 
  32. ^ "Properties of Different Types of Masks" (PDF). Government of New South Wales Clinical Excellence Commission. February 2020. Archived from the original (PDF) on 31 March 2020.
  33. ^ Jung J (17 March 2020). "KAIST Researchers Develop Highly Reusable Mask Filter". KoreaTechToday.
  34. ^ a b c "Recommended Guidance for Extended Use and Limited Reuse of N95 Filtering Facepiece Respirators in Healthcare Settings". NIOSH Workplace Safety and Health Topic. Centres for Disease Control and Prevention. 27 March 2020.
  35. ^ a b "Coronavirus Disease 2019 (COVID-19)". Centers for Disease Control and Prevention. 11 February 2020.
  36. ^ "Not Enough Face Masks Are Made In America To Deal With Coronavirus". NPR. 5 March 2020. Retrieved 10 April 2020.
  37. ^ "Chinese mask makers use loopholes to speed up regulatory approval". Financial Times. 1 April 2020. Retrieved 10 April 2020.
  38. ^ Long Y, Hu T, Liu L, Chen R, Guo Q, Yang L, et al. (May 2020). "Effectiveness of N95 respirators versus surgical masks against influenza: A systematic review and meta-analysis". Journal of Evidence-Based Medicine. 13 (2): 93–101. doi:10.1111/jebm.12381. PMC 7228345. PMID 32167245.
  39. ^ Gawn J (2008). "Evaluating the protection afforded by surgical masks against influenza bioaerosols" (PDF). UK's Health and Safety Executive.
  40. ^ Robertson P (15 March 2020). "Comparison of Mask Standards, Ratings, and Filtration Effectiveness". Smart Air Filters.
  41. ^ "YY 0469-2011 医用外科口罩.pdf". max.book118.com.
  42. ^ "YY/T 0969-2013: PDF in English". chinesestandard.net.
  43. ^ Mueller AV, Eden MJ, Oakes JM, Bellini C, Fernandez LA (September 2020). "Quantitative Method for Comparative Assessment of Particle Removal Efficiency of Fabric Masks as Alternatives to Standard Surgical Masks for PPE". Matter. 3 (3): 950–962. doi:10.1016/j.matt.2020.07.006. PMC 7346791. PMID 32838296.
  44. ^ a b Clapp PW, Sickbert-Bennett EE, Samet JM, Berntsen J, Zeman KL, Anderson DJ, et al. (April 2021). "Evaluation of Cloth Masks and Modified Procedure Masks as Personal Protective Equipment for the Public During the COVID-19 Pandemic". JAMA Internal Medicine. 181 (4): 463–469. doi:10.1001/jamainternmed.2020.8168. PMC 7729588. PMID 33300948.
  45. ^ Brooks JT, Beezhold DH, Noti JD, Coyle JP, Derk RC, Blachere FM, et al. (February 2021). "Maximizing Fit for Cloth and Medical Procedure Masks to Improve Performance and Reduce SARS-CoV-2 Transmission and Exposure, 2021". MMWR. Morbidity and Mortality Weekly Report. 70 (7): 254–257. doi:10.15585/mmwr.mm7007e1. PMC 7891692. PMID 33600386.
  46. ^ Cavalcanti G, Cocciole C, Cole C, Forgues A, Jaqua V, Jones-Davis D, et al. (2021). Design, Make, Protect: A report on the Open Source Maker and Manufacturer Response to the COVID-19 PPE Crisis (PDF). Open Source Medical Supplies & Nation of Makers. pp. 22, 46. Retrieved 17 June 2021.
  47. ^ Hyun C, Jensen MM, Yang K, Weaver JC, Wang X, Kudo Y, et al. (2023). "The Ultra fit community mask-Toward maximal respiratory protection via personalized face fit". PLOS ONE. 18 (3): e0281050. Bibcode:2023PLoSO..1881050H. doi:10.1371/journal.pone.0281050. ISSN 1932-6203. PMC 10016631. PMID 36920944.
  48. ^ "NIOSH-Approved N95 Particulate Filtering Facepiece Respirators – A Suppliers List". U.S. National Institute for Occupational Safety and Health. 19 March 2020. Retrieved 27 March 2020.
  49. ^ "Respirator Trusted-Source: Selection FAQs". U.S. National Institute for Occupational Safety and Health. 12 March 2020. Retrieved 28 March 2020.
  50. ^ Naveed H, Scantling-Birch Y, Lee H, Nanavaty MA (July 2020). "Controversies regarding mask usage in ophthalmic units in the United Kingdom during the COVID-19 pandemic". Eye. 34 (7): 1172–1174. doi:10.1038/s41433-020-0892-2. PMC 7179380. PMID 32327740.
  51. ^ a b c Zie J (19 March 2020). "World Depends on China for Face Masks But Can Country Deliver?". Voice of America.
  52. ^ Feng E (16 March 2020). "COVID-19 Has Caused A Shortage Of Face Masks. But They're Surprisingly Hard To Make". NPR.
  53. ^ "Comparison of FFP2, KN95, and N95 and Other Filtering Facepiece Respirator Classes" (PDF). 3M Technical Data Bulletin. 1 January 2020. Retrieved 28 March 2020.
  54. ^ "Strategies for Optimizing the Supply of N95 Respirators: Crisis/Alternate Strategies". U.S. Centers for Disease Control and Prevention. 17 March 2020. Retrieved 28 March 2020.
  55. ^ Collis B, Tacey M, McGrath C, Madigan V, Kainer M, Tramontana A, et al. (10 August 2023). "P2/N95 fit testing and the risk of COVID-19 in Healthcare Workers". Infection, Disease & Health. 29 (1): S2468–0451(23)00042–1. doi:10.1016/j.idh.2023.07.005. ISSN 2468-0869. PMID 37573216. S2CID 260820928.
  56. ^ Martin TC, Curtin G, Martin NK, Torriani FJ (30 August 2023). "Annual N95 respirator fit-testing: an unnecessary burden on healthcare". Infection Control and Hospital Epidemiology. 45 (2): 250–252. doi:10.1017/ice.2023.187. ISSN 1559-6834. PMC 10877532. PMID 37646178. S2CID 261337008.
  57. ^ a b Patel RB, Skaria SD, Mansour MM, Smaldone GC (July 2016). "Respiratory source control using a surgical mask: An in vitro study". Journal of Occupational and Environmental Hygiene. 13 (7): 569–576. doi:10.1080/15459624.2015.1043050. PMC 4873718. PMID 26225807.
  58. ^ "Interim Infection Prevention and Control Recommendations for Patients with Suspected or Confirmed Coronavirus Disease 2019 (COVID-19) in Healthcare Settings". Centers for Disease Control and Prevention (CDC). 18 May 2020. Retrieved 8 June 2020.
  59. ^ Mills S (10 April 2020). "Researchers looking at innovative ways to sterilize single-use masks". Canadian Broadcasting Corporation.
  60. ^ a b c "Considerations for Wearing Masks". Centers for Disease Control and Prevention. 7 August 2020. Archived from the original on 7 August 2020.
  61. ^ Lindsley WG, Blachere FM, Law BF, Beezhold DH, Noti JD (7 January 2021). "Efficacy of face masks, neck gaiters and face shields for reducing the expulsion of simulated cough-generated aerosols". Aerosol Science and Technology. 55 (4): 449–457. Bibcode:2021AerST..55..449L. doi:10.1080/02786826.2020.1862409. PMC 9345365. PMID 35924077.
  62. ^ Lindsley WG, Noti JD, Blachere FM, Szalajda JV, Beezhold DH (3 August 2014). "Efficacy of face shields against cough aerosol droplets from a cough simulator". Journal of Occupational and Environmental Hygiene. 11 (8): 509–518. doi:10.1080/15459624.2013.877591. PMC 4734356. PMID 24467190. Cited in Garcia Godoy LR, Jones AE, Anderson TN, Fisher CL, Seeley KM, Beeson EA, et al. (May 2020). "Facial protection for healthcare workers during pandemics: a scoping review". BMJ Global Health. 5 (5): e002553. doi:10.1136/bmjgh-2020-002553. PMC 7228486. PMID 32371574.
  63. ^ a b c d Chu DK, Akl EA, Duda S, Solo K, Yaacoub S, Schünemann HJ (June 2020). "Physical distancing, face masks, and eye protection to prevent person-to-person transmission of SARS-CoV-2 and COVID-19: a systematic review and meta-analysis". Lancet. 395 (10242): 1973–1987. doi:10.1016/S0140-6736(20)31142-9. PMC 7263814. PMID 32497510.
  64. ^ a b c "Elastomeric Respirators: Strategies During Conventional and Surge Demand Situations". Centers for Disease Control and Prevention. 13 October 2020. Archived from the original on 16 October 2020.
  65. ^ a b Chiang J, Hanna A, Lebowitz D, Ganti L (July 2020). "Elastomeric respirators are safer and more sustainable alternatives to disposable N95 masks during the coronavirus outbreak". International Journal of Emergency Medicine. 13 (1): 39. doi:10.1186/s12245-020-00296-8. PMC 7369563. PMID 32689926.
  66. ^ a b Howard BE (July 2020). "High-Risk Aerosol-Generating Procedures in COVID-19: Respiratory Protective Equipment Considerations". Otolaryngology–Head and Neck Surgery. 163 (1): 98–103. doi:10.1177/0194599820927335. PMID 32396451.
  67. ^ Mick P, Murphy R (May 2020). "Aerosol-generating otolaryngology procedures and the need for enhanced PPE during the COVID-19 pandemic: a literature review". Journal of Otolaryngology - Head & Neck Surgery. 49 (1): 29. doi:10.1186/s40463-020-00424-7. PMC 7212733. PMID 32393346.
  68. ^ Licina A, Silvers A, Stuart RL (August 2020). "Use of powered air-purifying respirator (PAPR) by healthcare workers for preventing highly infectious viral diseases-a systematic review of evidence". Systematic Reviews. 9 (1): 173. doi:10.1186/s13643-020-01431-5. PMC 7414632. PMID 32771035.
  69. ^ Staymates M (November 2020). "Flow visualization of an N95 respirator with and without an exhalation valve using schlieren imaging and light scattering". Physics of Fluids. 32 (11): 111703. Bibcode:2020PhFl...32k1703S. doi:10.1063/5.0031996. PMC 7684679. PMID 33244212.   Available under CC BY 4.0.
  70. ^ Portnoff L, Schall J, Brannen J, Suhon N, Strickland K, Meyers J (December 2020). Filtering Facepiece Respirators with an Exhalation Valve: Measurements of Filtration Efficiency to Evaluate Their Potential for Source Control (Report). U.S. Department of Health and Human Services, Centers for Disease Control and Prevention, National Institute for Occupational Safety and Health. doi:10.26616/NIOSHPUB2021107. DHHS (NIOSH) PUBLICATION NUMBER 2021-107.
  71. ^ "Face shields, masks with valves ineffective against COVID-19 spread: study". phys.org. Retrieved 8 October 2020.
  72. ^ Verma S, Dhanak M, Frankenfield J (September 2020). "Visualizing droplet dispersal for face shields and masks with exhalation valves". Physics of Fluids. 32 (9): 091701. arXiv:2008.00125. Bibcode:2020PhFl...32i1701V. doi:10.1063/5.0022968. PMC 7497716. PMID 32952381.
  73. ^ a b c "Using face masks in the community - Reducing COVID-19 transmission from potentially asymptomatic or pre-symptomatic people through the use of face masks". European Centre for Disease Prevention and Control. 8 April 2020. Archived from the original on 8 April 2020.
  74. ^ a b c d "Advice on the use of masks in the context of COVID-19". World Health Organization. 5 June 2020.
  75. ^ Ting V (4 April 2020). "To mask or not to mask: WHO makes U-turn while US, Singapore abandon pandemic advice and tell citizens to start wearing masks". South China Morning Post.
  76. ^ Wong-Shing K. "N95, KN95, KF94: The best masks to help avoid COVID now". CNET. Retrieved 13 January 2022.
  77. ^ "Cloth masks can help stop the spread of COVID-19, save lives and restore jobs". #Masks4All. Archived from the original on 25 September 2020. Retrieved 27 September 2020. The leading disease experts and governments representing 95% of the world's population (including the U.S. CDC) agree with the science and require/recommend masks because cloth (non-medical) masks are shown to limit the spread of COVID-19.
  78. ^ Advice on the use of masks in the community, during home care and in health care settings in the context of the novel coronavirus (2019-nCoV) outbreak: interim guidance, 29 January 2020 (Report). World Health Organization. 29 January 2020. hdl:10665/330987.
  79. ^ Advice on the use of masks in the community, during home care, and in health care settings in the context of COVID-19: interim guidance, 19 March 2020 (Report). World Health Organization. 19 March 2020. hdl:10665/331493.
  80. ^ a b Advice on the use of masks in the context of COVID-19: interim guidance, 6 April 2020 (Report). World Health Organization. 6 April 2020. hdl:10665/331693.
  81. ^ Keshtkar-Jahromi M, Sulkowski M, Holakouie-Naieni K (June 2020). "Public Masking: An Urgent Need to Revise Global Policies to Protect against COVID-19". The American Journal of Tropical Medicine and Hygiene. 102 (6): 1160–1161. doi:10.4269/ajtmh.20-0305. PMC 7253086. PMID 32323645.
  82. ^ a b c Winn P (1 April 2020). "Will the US ever mimic Asia's culture of 'universal masking'?". Public Radio International.
  83. ^ a b c Tufekci Z (17 March 2020). "Why Telling People They Don't Need Masks Backfired". The New York Times. Retrieved 12 April 2020.
  84. ^ Feng S, Shen C, Xia N, Song W, Fan M, Cowling BJ (May 2020). "Rational use of face masks in the COVID-19 pandemic". The Lancet. Respiratory Medicine. 8 (5): 434–436. doi:10.1016/S2213-2600(20)30134-X. PMC 7118603. PMID 32203710.
  85. ^ Flaskerud JH (September 2020). "Masks, Politics, Culture and Health". Issues in Mental Health Nursing. 41 (9): 846–849. doi:10.1080/01612840.2020.1779883. PMID 32644832.
  86. ^ Mantzari E, Rubin GJ, Marteau TM (July 2020). "Is risk compensation threatening public health in the covid-19 pandemic?". BMJ. 370: m2913. doi:10.1136/bmj.m2913. PMID 32713835.
  87. ^ Hunt K (27 July 2020). "Face mask wearers don't get lax about washing hands, study suggests". CNN.
  88. ^ Feuer W, Higgins-Dunn N (8 June 2020). "Asymptomatic spread of coronavirus is 'very rare', WHO says". CNBC.
  89. ^ "Q&A: Masks and COVID-19". World Health Organization. 7 June 2020. Archived from the original on 27 July 2020. For more details on fabrics, see also "Advice on the use of masks in the context of COVID-19". World Health Organization. 5 June 2020.
  90. ^ a b c d "Advice on the use of masks for children in the community in the context of COVID-19". World Health Organization. 21 August 2020. For an overview, see "Q&A: Children and masks related to COVID-19". World Health Organization. 21 August 2020.
  91. ^ "Q&A: Masks and COVID-19". World Health Organization. 7 June 2020. Archived from the original on 27 July 2020.
  92. ^ "Use of cloth face coverings to help slow the spread of COVID-19". Centers for Disease Control and Prevention. 3 April 2020.
  93. ^ López C. "Celebrities like Gwyneth Paltrow and Kate Hudson were criticized for wearing face masks early in the pandemic. Here's what changed". Business Insider.
  94. ^ "Transcript for CDC Telebriefing: CDC Update on Novel Coronavirus". Centers for Disease Control and Prevention. 12 February 2020.
  95. ^ "Fact check: Medical discharge document includes outdated CDC guidance on face masks". Reuters. 3 July 2020.
  96. ^ Fisher KA, Barile JP, Guerin RJ, Vanden Esschert KL, Jeffers A, Tian LH, et al. (July 2020). "Factors Associated with Cloth Face Covering Use Among Adults During the COVID-19 Pandemic - United States, April and May 2020". MMWR. Morbidity and Mortality Weekly Report. 69 (28): 933–937. doi:10.15585/mmwr.mm6928e3. PMID 32673303. S2CID 220606747.
  97. ^ a b Jingnan H (10 April 2020). "Why There Are So Many Different Guidelines For Face Masks For The Public". NPR.
  98. ^ Mills R (29 July 2020). "CDC director: Face masks "our most powerful tool" to fight COVID-19". 102.3 KRMG.
  99. ^ Brooks JT, Butler JC, Redfield RR (August 2020). "Universal Masking to Prevent SARS-CoV-2 Transmission-The Time Is Now". JAMA. 324 (7): 635–637. doi:10.1001/jama.2020.13107. PMC 8607819. PMID 32663243.
  100. ^ Henry TA (17 July 2020). "CDC's Dr. Redfield: This is why everyone should be wearing masks". American Medical Association.
  101. ^ "Personal Protective Equipment: Questions and Answers". Centers for Disease Control and Prevention. 8 August 2020. Archived from the original on 10 August 2020.
  102. ^ a b "Considerations for wearing cloth face coverings: help slow the spread of COVID-19". Centers for Disease Control and Prevention. 28 June 2020.
  103. ^ Miller SG (13 August 2020). "Does your mask have a valve on it? It won't stop the spread of coronavirus, CDC says". NBC News.
  104. ^ a b c d "Scientific Brief: Community Use of Cloth Masks to Control the Spread of SARS-CoV-2". Centers for Disease Control and Prevention. 10 November 2020.   This article incorporates text from this source, which is in the public domain.
  105. ^ "Interim Infection Prevention and Control Recommendations for Healthcare Personnel During the Coronavirus Disease 2019 (COVID-19) Pandemic". Centers for Disease Control and Prevention. 15 July 2020. Archived from the original on 30 July 2020.
  106. ^ "Strategies for Optimizing the Supply of N95 Respirators". Centers for Disease Control and Prevention. 28 June 2020. Archived from the original on 28 July 2020.   This article incorporates text from this source, which is in the public domain.
  107. ^ "When You've Been Fully Vaccinated". Centers for Disease Control and Prevention. 27 July 2021. Archived from the original on 28 July 2021.
  108. ^ Aubrey A (27 July 2021). "CDC Urges Vaccinated People To Mask Up Indoors In Places With High Virus Transmission". NPR.
  109. ^ "Interim Public Health Recommendations for Fully Vaccinated People". Centers for Disease Control and Prevention. 13 May 2021. Archived from the original on 14 May 2021.
  110. ^ Noguchi Y (20 May 2021). "The CDC Is Gambling On Relaxed Mask Rules To Get More People Vaccinated". NPR.
  111. ^ Bosman J, Mervosh S (18 May 2021). "New Honor System on Masks: 'Am I to Trust These People?'". The New York Times.
  112. ^ Iati M (15 May 2021). "The new mask guidance relies on an honor system. Do we trust each other enough to make it work?". The Washington Post.
  113. ^ Mandavilli A (25 February 2022). "The C.D.C. releases new guidance that will allow localities to ease masking and social distancing". The New York Times. ISSN 0362-4331. Retrieved 28 February 2022.
  114. ^ "CDC says Americans can now go unmasked in many parts of the country". NPR.org. Retrieved 28 February 2022.
  115. ^ Wetsman N (3 April 2020). "Masks may be good, but the messaging around them has been very bad". The Verge.
  116. ^ Jankowicz M (1 June 2020). "Fauci said US government held off promoting face masks because it knew shortages were so bad that even doctors couldn't get enough". Business Insider.
  117. ^ Zweig D (16 December 2021). "The CDC's Flawed Case for Wearing Masks in School". The Atlantic. Retrieved 15 June 2022.
  118. ^ Cohen J (27 March 2020). "Not wearing masks to protect against coronavirus is a 'big mistake'". Science.
  119. ^ "Mandatory mask-wearing now the norm in Europe as COVID-19 cases rise". euronews. 24 July 2020.
  120. ^ a b "Norway Makes First Face Mask Recommendation Since Pandemic Began". VOA News. 14 August 2020.
  121. ^ Vogel G (6 October 2020). "'It's been so, so surreal.' Critics of Sweden's lax pandemic policies face fierce backlash". Science. doi:10.1126/science.abf1247. S2CID 225148153.
  122. ^ "Using face masks in the community: first update - Effectiveness in reducing transmission of COVID-19". European Centre for Disease Prevention and Control. 15 February 2021. Archived from the original on 17 February 2021.
  123. ^ "Hoe iets 'wat geen bescherming biedt' toch landelijk geadviseerd werd" [How something 'that offers no protection' was nevertheless advised nationally]. nos.nl (in Dutch). 30 September 2020. Retrieved 24 February 2021.
  124. ^ Woolcot S. "Face Masks to Be Compulsory on Public Transport in the Netherlands". amsterdamshallowman.com.
  125. ^ "Why are the Nordic countries still not recommending face masks?". The Local dk. 30 July 2020.
  126. ^ Stoltenberg C (June 2020), "Should individuals in the community without respiratory symptoms wear facemasks to reduce the spread of COVID-19? – a rapid review" (PDF), Norwegian Institute of Public Health
  127. ^ "Denmark Recommends Face Masks On Public Transport". Barron's. 31 July 2020.
  128. ^ "No country for face masks: Nordics brush off mouth covers". medicalxpress. 30 July 2020.
  129. ^ "Tegnells vändning: Lämpligt med munskydd (om man är nära varandra)". Breakit (in Swedish). Retrieved 13 May 2021.
  130. ^ Lönnroth V (25 November 2020). "Tegnell: Då ska du bära munskydd på jobbet". Göteborgs-Posten (in Swedish). Retrieved 13 May 2021.
  131. ^ "Sweden does U-turn on face masks to fight virus". France 24. 18 December 2020.
  132. ^ "Munskydd i kollektivtrafiken från den 7 januari". Folkhalsomyndigheten. 30 December 2020. Archived from the original on 9 November 2021. Retrieved 18 January 2021.
  133. ^ "Statsminister Löfven besökte galleria fyra dagar före jul". 29 December 2020.
  134. ^ Razooq N (22 January 2021). "Hälften av resenärerna använder munskydd under rusningstid enligt SL". SVT Nyheter.
  135. ^ Pan E, Lindberg J (28 January 2021). "FHM:s generaldirektör åkte kollektivtrafik utan munskydd: "Genant"". SVT Nyheter (in Swedish).
  136. ^ "Nyheter24 avslöjar: Här åker Anders Tegnell tåg i rusningstrafik – utan munskydd". 4 February 2021.
  137. ^ Tang JW, Nicolle AD, Pantelic J, Jiang M, Sekhr C, Cheong DK, et al. (22 June 2011). "Qualitative real-time schlieren and shadowgraph imaging of human exhaled airflows: an aid to aerosol infection control". PLOS ONE. 6 (6): e21392. Bibcode:2011PLoSO...621392T. doi:10.1371/journal.pone.0021392. PMC 3120871. PMID 21731730.
  138. ^ Verma S, Dhanak M, Frankenfield J (June 2020). "Visualizing the effectiveness of face masks in obstructing respiratory jets". Physics of Fluids. 32 (6): 061708. Bibcode:2020PhFl...32f1708V. doi:10.1063/5.0016018. PMC 7327717. PMID 32624649.
  139. ^ Prather KA, Wang CC, Schooley RT (June 2020). "Reducing transmission of SARS-CoV-2". Science. 368 (6498): 1422–1424. Bibcode:2020Sci...368.1422P. doi:10.1126/science.abc6197. PMID 32461212.
  140. ^ a b c d e "Why healthy Chinese wearing face masks outdoors?". NHC.gov.cn. National Health Commission. 23 March 2020. Archived from the original on 10 April 2020. Retrieved 12 April 2020.
  141. ^ a b Cheng KK, Lam TH, Leung CC (April 2020). "Wearing face masks in the community during the COVID-19 pandemic: altruism and solidarity". Lancet. 399 (10336): e39–e40. doi:10.1016/S0140-6736(20)30918-1. PMC 7162638. PMID 32305074.
  142. ^ a b c "Scientific Brief: Community Use of Cloth Masks to Control the Spread of SARS-CoV-2". Centers for Disease Control and Prevention. 10 November 2020.
  143. ^ Gandhi M (23 June 2020). "Can people spread the coronavirus if they don't have symptoms? Five questions answered about asymptomatic COVID-19". The Conversation.
  144. ^ Hou YJ, Okuda K, Edwards CE, Martinez DR, Asakura T, Dinnon KH, et al. (July 2020). "SARS-CoV-2 Reverse Genetics Reveals a Variable Infection Gradient in the Respiratory Tract". Cell. 182 (2): 429–446.e14. doi:10.1016/j.cell.2020.05.042. PMC 7250779. PMID 32526206.
  145. ^ a b c Gandhi M, Beyrer C, Goosby E (October 2020). "Masks Do More Than Protect Others During COVID-19: Reducing the Inoculum of SARS-CoV-2 to Protect the Wearer". Journal of General Internal Medicine. 35 (10): 3063–3066. doi:10.1007/s11606-020-06067-8. PMC 7393808. PMID 32737790.
  146. ^ Greenhalgh T, Schmid MB, Czypionka T, Bassler D, Gruer L (April 2020). "Face masks for the public during the covid-19 crisis". BMJ. 369: m1435. doi:10.1136/bmj.m1435. PMID 32273267.
  147. ^ Javid B, Weekes MP, Matheson NJ (April 2020). "Covid-19: should the public wear face masks?". BMJ. 369: m1442. doi:10.1136/bmj.m1442. PMID 32273278. S2CID 215516356.
  148. ^ Clase, C.M., R.C.L. Beale, M.B. Dolovich, E.L.F. Fu, M.J. Jardine, M. Joseph, J.F.E. Mann, R. Pecoits-Filho, W. C. Winkelmayer, and J. J. Carrero. 2020. 'Cloth masks may prevent transmission of COVID-19: an evidence-based, risk-based approach'. Retrieved 18 July 2020. PMID 32441991
  149. ^ Setti L, Passarini F, De Gennaro G, Barbieri P, Perrone MG, Borelli M, et al. (April 2020). "Airborne Transmission Route of COVID-19: Why 2 Meters/6 Feet of Inter-Personal Distance Could Not Be Enough". International Journal of Environmental Research and Public Health. 17 (8): 2932. doi:10.3390/ijerph17082932. PMC 7215485. PMID 32340347.
  150. ^ a b Leung CC, Cheng KK, Lam TH, Migliori GB (June 2020). "Mask wearing to complement social distancing and save lives during COVID-19". The International Journal of Tuberculosis and Lung Disease. 24 (6): 556–558. doi:10.5588/ijtld.20.0244. PMID 32553007. S2CID 219967740.
  151. ^ "How to avoid touching your face so much". BBC News. 18 March 2020.
  152. ^ Chan KH, Yuen KY (August 2020). "COVID-19 epidemic: disentangling the re-emerging controversy about medical facemasks from an epidemiological perspective". International Journal of Epidemiology. 49 (4): 1063–1066. doi:10.1093/ije/dyaa044. PMC 7184463. PMID 32232402.
  153. ^ Moriyama M, Hugentobler WJ, Iwasaki A (September 2020). "Seasonality of Respiratory Viral Infections". Annual Review of Virology. 7 (1): 83–101. doi:10.1146/annurev-virology-012420-022445. PMID 32196426.
  154. ^ Chan NC, Li K, Hirsh J (December 2020). "Peripheral Oxygen Saturation in Older Persons Wearing Nonmedical Face Masks in Community Settings". JAMA. 324 (22): 2323–2324. doi:10.1001/jama.2020.21905. PMC 7600049. PMID 33125030.
  155. ^ a b c Cash-Goldwasser S, Reingold AL, Luby SP, Jackson LA, Frieden TR (31 October 2023). "Masks During Pandemics Caused by Respiratory Pathogens—Evidence and Implications for Action". JAMA Network Open. 6 (10): e2339443. doi:10.1001/jamanetworkopen.2023.39443. ISSN 2574-3805. PMID 37906187. S2CID 264673924.
  156. ^ a b "COVID-19: examining the effectiveness of non-pharmaceutical interventions" (PDF). The Royal Society.
  157. ^ Ollila HM, Partinen M, Koskela J, Borghi J, Savolainen R, Rotkirch A, et al. (1 December 2022). "Face masks to prevent transmission of respiratory infections: Systematic review and meta-analysis of randomized controlled trials on face mask use". PLOS ONE. 17 (12): e0271517. Bibcode:2022PLoSO..1771517O. doi:10.1371/journal.pone.0271517. PMC 9714953. PMID 36454947.
  158. ^ Sandlund J, Duriseti R, Ladhani SN, Stuart K, Noble J, Høeg TB (December 2023). "Child mask mandates for COVID-19: a systematic review". Arch Dis Child (Systematic review). 109 (3): e2. doi:10.1136/archdischild-2023-326215. PMC 10894839. PMID 38050026.
  159. ^ Escandón K, Rasmussen AL, Bogoch II, Murray EJ, Escandón K, Popescu SV, et al. (July 2021). "COVID-19 false dichotomies and a comprehensive review of the evidence regarding public health, COVID-19 symptomatology, SARS-CoV-2 transmission, mask wearing, and reinfection". BMC Infect Dis (Review). 21 (1): 710. doi:10.1186/s12879-021-06357-4. PMC 8314268. PMID 34315427.
  160. ^ Ford N, Holmer HK, Chou R, Villeneuve PJ, Baller A, Van Kerkhove M, et al. (August 2021). "Mask use in community settings in the context of COVID-19: A systematic review of ecological data". eClinicalMedicine. 38: 101024. doi:10.1016/j.eclinm.2021.101024. PMC 8287197. PMID 34308320.
  161. ^ Sharma SK, Mishra M, Mudgal SK (2020). "Efficacy of cloth face mask in prevention of novel coronavirus infection transmission: A systematic review and meta-analysis". Journal of Education and Health Promotion. 9: 192. doi:10.4103/jehp.jehp_533_20. PMC 7497125. PMID 33015206.
  162. ^ a b Nanda A, Hung I, Kwong A, Man VC, Roy P, Davies L, et al. (May 2021). "Efficacy of surgical masks or cloth masks in the prevention of viral transmission: Systematic review, meta-analysis, and proposal for future trial". Journal of Evidence-Based Medicine. 14 (2): 97–111. doi:10.1111/jebm.12424. PMC 8014575. PMID 33565274.
  163. ^ Wang Y, Tian H, Zhang L, Zhang M, Guo D, Wu W, et al. (May 2020). "Reduction of secondary transmission of SARS-CoV-2 in households by face mask use, disinfection and social distancing: a cohort study in Beijing, China". BMJ Global Health. 5 (5): e002794. doi:10.1136/bmjgh-2020-002794. PMC 7264640. PMID 32467353. Cited in "Scientific Brief: Community Use of Cloth Masks to Control the Spread of SARS-CoV-2". Centers for Disease Control and Prevention. 10 November 2020.   This article incorporates text from this source, which is in the public domain.
  164. ^ Doung-Ngern P, Suphanchaimat R, Panjangampatthana A, Janekrongtham C, Ruampoom D, Daochaeng N, et al. (November 2020). "Case-Control Study of Use of Personal Protective Measures and Risk for SARS-CoV 2 Infection, Thailand". Emerging Infectious Diseases. 26 (11): 2607–2616. doi:10.3201/eid2611.203003. PMC 7588529. PMID 32931726. Cited in "Scientific Brief: Community Use of Cloth Masks to Control the Spread of SARS-CoV-2". Centers for Disease Control and Prevention. 10 November 2020.   This article incorporates text from this source, which is in the public domain.
  165. ^ Lio CF, Cheong HH, Lei CI, Lo IL, Yao L, Lam C, et al. (April 2021). "Effectiveness of personal protective health behaviour against COVID-19". BMC Public Health. 21 (1): 827. doi:10.1186/s12889-021-10680-5. PMC 8082215. PMID 33926406.
  166. ^ Schwartz KL, Murti M, Finkelstein M, Leis JA, Fitzgerald-Husek A, Bourns L, et al. (April 2020). "Lack of COVID-19 transmission on an international flight". CMAJ. 192 (15): E410. doi:10.1503/cmaj.75015. PMC 7162437. PMID 32392504. Freedman DO, Wilder-Smith A (December 2020). "In-flight transmission of SARS-CoV-2: a review of the attack rates and available data on the efficacy of face masks". Journal of Travel Medicine. 27 (8): taaa178. doi:10.1093/jtm/taaa178. PMC 7543400. PMID 32975554. Cited in "Scientific Brief: Community Use of Cloth Masks to Control the Spread of SARS-CoV-2". Centers for Disease Control and Prevention. 10 November 2020.   This article incorporates text from this source, which is in the public domain.
  167. ^ Adenaiye OO, Lai J, de Mesquita PJ, Hong F, Youssefi S, German J, et al. (September 2021). "Infectious SARS-CoV-2 in Exhaled Aerosols and Efficacy of Masks During Early Mild Infection". Clinical Infectious Diseases. 75 (1): e241–e248. doi:10.1093/cid/ciab797. medRxiv 10.1101/2021.08.13.21261989. PMC 8522431. PMID 34519774. S2CID 236994796.
  168. ^ "Face masks slow spread of COVID-19; types of masks, length of use matter". phys.org. Retrieved 9 December 2020.
  169. ^ Kumar S, Lee HP (November 2020). "The perspective of fluid flow behavior of respiratory droplets and aerosols through the facemasks in context of SARS-CoV-2". Physics of Fluids. 32 (11): 111301. arXiv:2010.06385. Bibcode:2020PhFl...32k1301K. doi:10.1063/5.0029767. PMC 7713871. PMID 33281434.
  170. ^ Willis K. "If you haven't been double-masking, new CDC study shows why you should". The Atlanta Journal-Constitution.
  171. ^ a b "How to Wear Masks". Centers for Disease Control and Prevention. 7 August 2020. Archived from the original on 27 September 2020. Retrieved 28 September 2020.
  172. ^ Parker-Pope T (8 April 2020). "How NOT to Wear a Mask". The New York Times.
  173. ^ Malnick E (20 June 2020). "Commuters are wearing masks incorrectly". The Daily Telegraph.
  174. ^ de Courten B, de Courten M, Apostolopoulos V (12 May 2020). "Are you wearing gloves or a mask to the shops? You might be doing it wrong". The Conversation.
  175. ^ Lai J (18 May 2020). "All the ways you're wearing your coronavirus face mask wrong and how to do it properly". Inquirer.
  176. ^ a b c Cuda A (1 July 2020). "Health experts: COVID masks are only effective if worn properly". Connecticut Post. Archived from the original on 10 July 2021. Retrieved 15 September 2020.
  177. ^ Breen K (29 September 2020). "Coronavirus face coverings under the nose equivalent to 'not wearing a mask': experts". Global News.
  178. ^ 谢斌 张纯 (21 January 2020). "一罩难求:南都民调实测走访发现,线上线下口罩基本卖脱销". 南方都市报. Retrieved 21 January 2020.
  179. ^ 徐榆涵 (23 January 2020). "全球各地瘋搶口罩 專家:不必買N95". 聯合報. Archived from the original on 25 January 2020. Retrieved 25 January 2020.
  180. ^ 刘灏 (21 January 2020). "广东市场监管部门:将坚决打击囤积居奇、哄抬价格等行为". 南方网. Retrieved 21 January 2020.
  181. ^ "市场价格行为提醒书". n.d. Archived from the original on 27 January 2020.
  182. ^ 陈泽云 (22 January 2020). "口罩买不到怎么办?这些药店平台春节期间持续供应". 金羊网. Archived from the original on 22 January 2020. Retrieved 22 January 2020.
  183. ^ 新京报 (22 January 2020). "京东:禁止第三方商家口罩涨价". 新京报网. Archived from the original on 27 January 2020. Retrieved 22 January 2020.
  184. ^ 新京报 (22 January 2020). "苏宁易购:口罩等健康类商品禁涨价,并开展百亿补贴". 新京报网. Archived from the original on 22 January 2020. Retrieved 22 January 2020.
  185. ^ 新京报 (22 January 2020). "拼多多:对口罩等产品进行监测,恶意涨价者将下架". 新京报网. Archived from the original on 22 January 2020. Retrieved 22 January 2020.
  186. ^ a b c Khazan O (10 April 2020). "Why We're Running Out of Masks". The Atlantic.
  187. ^ Miroff N (1 April 2020). "Protective gear in the national stockpile is nearly depleted, DHS officials say". The Washington Post. Archived from the original on 1 April 2020.
  188. ^ "U.S. sent millions of face masks to China early this year, ignoring pandemic warning signs". The Washington Post. ISSN 0190-8286. Retrieved 1 November 2022.
  189. ^ a b c d e f "Pénurie de masques : une responsabilité partagée par les gouvernements". Public Senat (in French). 23 March 2020. Retrieved 6 April 2020.
  190. ^ BFMTV. "Pénurie de masques: pourquoi la France avait décidé de ne pas renouveler ses stocks il y a neuf ans" (in French). BFMTV. Retrieved 6 April 2020.
  191. ^ Roy S, Barotte N (19 March 2020). "Quand l'État stratège a renoncé à renouveler ses stocks de masques". Le Figaro (in French). Retrieved 6 April 2020.
  192. ^ a b "France to produce 40 million face masks by end of April for domestic battle against Covid-19". Radio France Internationale. 31 March 2020. Retrieved 6 April 2020.
  193. ^ "Covid-19: French lawmakers to investigate where one and a half billion masks sent". Radio France Internationale. 1 April 2020. Retrieved 6 April 2020.
  194. ^ "Pénurie de masques : les raisons d'un "scandale d'État"". Franceinter.fr. n.d. Retrieved 6 April 2020.
  195. ^ "National Case Study: France's Maker Response Against COVID-19". Open Source Medical Supplies. Retrieved 18 March 2021.
  196. ^ a b "Countries reject Chinese-made equipment". BBC News. 30 March 2020.
  197. ^ a b c Choi D (2 April 2020). "Chinese government rejects allegations that its face masks were defective, tells countries to 'double check' instructions". Business Insider France.
  198. ^ "Trudeau says Canada will not pay full price for 8 million sub-standard masks". CTVNews. 9 May 2020.
  199. ^ Bronskill J (8 May 2020). "Federal government rejects 8 million N95 masks from single distributor". Canadian Broadcasting Corporation.
  200. ^ a b Rohrlich J (27 April 2020). "An Indiana hospital theft shows face masks and hand sanitizer are now as sought-after as drugs". Quartz.
  201. ^ "Theft of masks, sanitizer at Naval Medical Center San Diego lead to bag checks for staff". The San Diego Union-Tribune. 10 April 2020.
  202. ^ "Thefts in hospitals lead to lockup of masks, protective gear amid COVID-19 supply shortage | CBC News".
  203. ^ "Where is all the PPE?". AAMC.
  204. ^ "2,000 surgical masks stolen from hospital in French city of Marseille". Al Arabiya English. 4 March 2020.
  205. ^ "Upstate NY hospital worker arrested, accused of stealing face masks". syracuse. 30 March 2020.
  206. ^ "West Java hospital employees arrested for allegedly stealing hundreds of boxes of masks". The Jakarta Post.
  207. ^ Catoura C. "Ex-healthcare worker accused of stealing personal protective equipment arrested". CBS46 News Atlanta. Archived from the original on 3 November 2020. Retrieved 23 October 2020.
  208. ^ "Charlie Norwood VA Medical Center employee arrested for stealing personal protective equipment". 10 April 2020.
  209. ^ "Hospital employee steals personal protective equipment worth $1,700, police say". FOX 10 Phoenix. 4 April 2020.
  210. ^ Phillips D (5 April 2020). "Hospital worker stole personal protective equipment, cops say". Sun-Sentinel.
  211. ^ "Ghana hospital workers cash in on PPE amid coronavirus". BBC News. 10 August 2020.
  212. ^ Brown A (21 October 2020). "2 SC men charged for allegedly stealing masks from federal law enforcement training center". Post and Courier.
  213. ^ Johnson M (26 March 2020). "Feds have 1.5 million expired N95 masks in storage despite CDC clearing them for use on COVID-19: report". The Hill. Retrieved 12 April 2020.
  214. ^ Evan M, Hufford A (7 March 2020). "Critical Component of Protective Masks in Short Supply – The epidemic has driven up demand for material in N95 filters; 'everyone thinks there is this magic factory somewhere'". The Wall Street Journal.
  215. ^ a b c Fabian J, Clough R (2 April 2020). "Trump Attacks 3M Over Mask Production, Drawing Company Pushback". Bloomberg L.P.
  216. ^ Whalen J, Helderman RS, Hamburger T (3 April 2020). "Inside Americas Mask Crunch". The Washington Post.
  217. ^ Halon Y (3 April 2020). "Florida emergency management official says 3M selling masks to foreign countries: 'We're chasing ghosts'". Fox News. Retrieved 4 April 2020.
  218. ^ "Interview With Jared Moskowitz, Director of Florida's Division of Emergency Management". WFOR-TV. 3 April 2020. Retrieved 4 April 2020.
  219. ^ Man A (5 April 2020). "Florida emergency management chief says state will have enough ICU beds and ventilators". Sun-Sentinel. Retrieved 5 April 2020.
  220. ^ DiSalvo D (30 March 2020). "I Spent A Day In The Coronavirus-Driven Feeding Frenzy Of N95 Mask Sellers And Buyers And This Is What I Learned". Forbes. Retrieved 8 April 2020.
  221. ^ Bertrand N, Orr G, Lippman D, Toosi N (31 March 2020). "Pence task force freezes coronavirus aid amid backlash". Politico. Retrieved 8 April 2020.
  222. ^ a b c Jessica Contrera (21 September 2020). "The N95 shortage America can't seem to fix". The Washington Post. Archived from the original on 21 September 2020.
  223. ^ Chase B (28 September 2020). "N95 mask shortage scares health care workers ahead of projected COVID-19 spike". Chicago Sun-Times.
  224. ^ Marisa Iati (2 February 2021). "Why the U.S. still has a shortage of N95 masks". The Washington Post.
  225. ^ Joseph G. Allen (26 January 2021). "Opinion | Everyone should be wearing N95 masks now". The Washington Post.
  226. ^ Dhillon RS, Karan A, Beier D, Srikrishna D (17 February 2021). "Perspective | The government can – and should – send high-quality masks to every American". The Washington Post. Retrieved 19 February 2021.
  227. ^ Stolberg SG (19 January 2022). "Covid Live Updates: Biden Administration to Issue 400 Million Masks From National Stockpile - The nonsurgical N95 masks will be available free at community health centers and retail pharmacies across the United States". The New York Times. Retrieved 19 January 2022.
  228. ^ Betschka J, Fröhlich A (3 April 2020). "Berlins Innensenator spricht von 'moderner Piraterie'". Der Tagesspiegel (in German).
  229. ^ "Schutzmasken konfisziert? Schwere Vorwürfe aus Berlin: Jetzt reagiert das Weiße Haus". t-online.de. 4 April 2020.
  230. ^ Fröhlich A (4 April 2020). "200,000 respirators not confiscated: Delivery for Berlin police was bought in Thailand at a better price". Der Tagesspiegel.
  231. ^ "Berlin lets mask slip on feelings for Trump's America". Politico Europe. 10 April 2020.
  232. ^ Tisdall S (12 April 2020). "US's global reputation hits rock-bottom over Trump's coronavirus response". The Guardian.
  233. ^ "National Case Study: Germany's Maker Response against COVID-19". Open Source Medical Supplies. Retrieved 18 March 2021.
  234. ^ "COVID-19: Coquitlam company retools, will be first in Canada to produce N95 respirators". 6 April 2020. Retrieved 6 April 2020.
  235. ^ "As imports hit roadblock, when can Canada make its own N95 masks?". Toronto Star. 23 May 2020.
  236. ^ Bradsher K, Alderman L (2 April 2020). "The World Needs Masks. China Makes Them, but Has Been Hoarding Them". The New York Times. Retrieved 7 May 2020. China made half the world's masks before the coronavirus emerged there, and it has expanded production nearly 12-fold since then.
  237. ^ For example: "Face mask production shows no sign of stopping". PAhomepage. Nexstar Broadcasting, Inc. 22 April 2020. Retrieved 7 May 2020. [...] Martz Technologies in Berwick [in Pennsylvania] [...] turned their warehouse into a face mask factory.
  238. ^ Enrich D, Abrams R, Kurutz S (25 March 2020). "A Sewing Army, Making Masks for America". The New York Times.
  239. ^ Levy J (4 May 2020). "Need for masks spawns cottage industry". Republican-American. Waterbury, CT: Republican American. Archived from the original on 2 November 2020. Retrieved 7 May 2020. Production of face masks is becoming a cottage industry of sorts with some hybrid operations that both donate and sell the sought-after coverings.
  240. ^ Bhanoo S (1 April 2020). "Which DIY mask pattern should you use? Even experts can't pick one to recommend". The Washington Post.
  241. ^ "Master Maskmaking Guide". Makemasks. Archived from the original on 14 August 2020. Retrieved 9 May 2020. well-known patterns such as the Deaconess, A.B. mask (For a nurse, by a nurse), We Can Sew It, the Cynthia, and the Erin ... Full Pattern Library
  242. ^ a b Cissy Z (12 June 2020). "Coronavirus: wheels come off China's mask-making gravy train, as low-end manufacturers count their losses". South China Morning Post.
  243. ^ "Makers Are 3D Printing Ventilator Gear and Sewing Masks to Fight the Coronavirus". Time. Retrieved 29 December 2021.
  244. ^ For example: Blanchard B (1 April 2020). "Taiwan to spend $35 billion fighting virus, to donate 10 million masks". Reuters. Archived from the original on 3 April 2020. Retrieved 7 May 2020. Taiwan [...] said it would donate ten million face masks to the most needy countries. [...] The Foreign Ministry said seven million masks would be sent to Europe, including Spain, Italy and Britain, while two million would go to the United States, and the rest to the small band of countries which maintain formal diplomatic ties with Taiwan [...].
  245. ^ Kavilanz P (7 August 2020). "Etsy's on fire as reusable face mask sales surge". CNN. Retrieved 25 August 2020.
  246. ^ Wong SH, Teoh J, Leung CH, Wu W, Yip B, Wong M, et al. (1 August 2020). "COVID-19 and Public Interest in Face Mask Use". American Journal of Respiratory and Critical Care Medicine. 202 (3): 453–455. doi:10.1164/rccm.202004-1188LE. PMC 7397798. PMID 32539430.
  247. ^ Yeung A, Parvanov ED, Horbańczuk JO, Kletecka-Pulker M, Kimberger O, Willschke H, et al. (2023). "Public interest in different types of masks and its relationship with pandemic and policy measures during the COVID-19 pandemic: a study using Google Trends data". Frontiers in Public Health. 11: 1010674. doi:10.3389/fpubh.2023.1010674. PMC 10286862. PMID 37361173.
  248. ^ a b c d Onishi N, Méheut C (9 April 2020). "Mask-Wearing Is a Very New Fashion in Paris (and a Lot of Other Places)". The New York Times.
  249. ^ a b Wong T (31 March 2020). "Why some countries wear face masks and others don't". BBC News.
  250. ^ a b c d Zheng S (14 March 2020). "Face mask culture during the coronavirus: East vs West". South China Morning Post.
  251. ^ a b Zhao X, Knobel P (June 2021). "Face mask wearing during the COVID-19 pandemic: comparing perceptions in China and three European countries". Translational Behavioral Medicine. 11 (6): 1199–1204. doi:10.1093/tbm/ibab043. PMC 8240840. PMID 33963866.
  252. ^ Borunda A (27 April 2020). "America's face-mask culture is changing, and their meaning changes too". National Geographic. Archived from the original on 29 April 2020.
  253. ^ Gulland A (3 August 2020). "Wearing a face mask is an act of solidarity, WHO chief says". The Daily Telegraph.
  254. ^ Kolstoe S (20 May 2020). "Coronavirus: wearing a cloth face mask is less about science and more about solidarity". The Conversation.
  255. ^ "Lessons From Slovakia – Where Leaders Wear Masks". The Atlantic. 13 May 2020.
  256. ^ Leung H (12 March 2020). "Why Face Masks Are Encouraged in Asia, but Shunned in the U.S." Time.
  257. ^ Barceló J, Sheen GC (6 May 2020). "Voluntary adoption of social welfare-enhancing behavior: Mask-wearing in Spain during the COVID-19 outbreak". PLOS ONE. 15 (12): e0242764. Bibcode:2020PLoSO..1542764B. doi:10.1371/journal.pone.0242764. PMC 7707551. PMID 33259531.
  258. ^ a b c van der Westhuizen HM, Kotze K, Tonkin-Crine S, Gobat N, Greenhalgh T (August 2020). "Face coverings for covid-19: from medical intervention to social practice". BMJ. 370: m3021. doi:10.1136/bmj.m3021. PMID 32816815.
  259. ^ a b c Eisenmann C, Meyer C (2020). "Wearing a Face Mask in Everyday Life – About Recalibrations in the Interactional Infrastructure of Global Cooperation". Global Cooperation Research - A Quarterly Magazine. 2 (2). ISSN 2629-3080. Archived from the original on 26 October 2020. Retrieved 23 November 2020.
  260. ^ a b Tett G (1 April 2020). "Why wearing masks may be the way forward". Financial Times.
  261. ^ Friedman U (2 April 2020). "Face Masks Are In". The Atlantic.
  262. ^ Howard J (28 March 2020). "Simple DIY masks could help flatten the curve. We should all wear them in public". The Washington Post.
  263. ^ "New local website aims to promote mask wearing to help flatten the curve". News24. 7 April 2020. Archived from the original on 14 April 2020. Retrieved 23 April 2020.
  264. ^ a b c d e Betsch C, Korn L, Sprengholz P, Felgendreff L, Eitze S, Schmid P, et al. (September 2020). "Social and behavioral consequences of mask policies during the COVID-19 pandemic". Proceedings of the National Academy of Sciences of the United States of America. 117 (36): 21851–21853. Bibcode:2020PNAS..11721851B. doi:10.1073/pnas.2011674117. PMC 7486713. PMID 32820078.
  265. ^ "Coronavirus: To Mask Or Not To Mask? #Masks4All Seeks Everyone To Cover Their Mouths". CBS New York. 31 March 2020.
  266. ^ Bhattarai A (8 July 2020). "Retail workers are being pulled into the latest culture war: Getting customers to wear masks". The Washington Post.
  267. ^ Wolford B (30 June 2020). "Customers 'aggressive' over face mask policies force fed-up restaurants to close". Miami Herald.
  268. ^ Norfleet N (1 July 2020). "As COVID-19 mask debate rages on, retailers reluctantly take brunt of enforcement". Star Tribune.
  269. ^ Taylor K, Moné B (21 May 2020). "Workers at chains like Kroger, Costco, and Waffle House are on the front lines of an increasingly violent war between mask supporters and opponents". Business Insider.
  270. ^ "Man dies after being shoved to the ground in New York mask altercation". The Guardian. 6 October 2020.
  271. ^ Gibson K (23 July 2020). "U.S. retailers badly want shoppers to wear masks. Getting them to comply is another story". CBS News.
  272. ^ a b c Zine J (3 June 2020). "Unmasking the racial politics of the coronavirus pandemic". The Conversation.
  273. ^ Burton N (6 March 2020). "Why Asians in masks should not be the "face" of the coronavirus". Vox.
  274. ^ Nabong P (30 March 2020). "Wearing a mask while Asian". Chicago Reader.
  275. ^ Young I (13 May 2020). "Coronavirus: Asian women in Canada are abused, punched and spat on. Is it racist maskaphobia?". South China Morning Post. Retrieved 3 June 2020.
  276. ^ Taylor DB (14 April 2020). "For Black Men, Fear That Masks Will Invite Racial Profiling". The New York Times.
  277. ^ de la Garza A (16 April 2020). "For Black Men, Homemade Masks May Be a Risk All Their Own". Time.
  278. ^ Alfonso III F (7 April 2020). "Why some people of color say they won't wear homemade masks". CNN.
  279. ^ a b Roffe E (15 July 2020). "Face masks: 'Impact on the deaf community will be vast'". Bedford Independent. Retrieved 24 July 2020.
  280. ^ a b Taylor-Coleman J (26 May 2020). "Call for clear face masks to be 'the norm'". BBC News.
  281. ^ Gremer L (14 October 2021). "Mask-wearing causes deaf, hard-of-hearing individuals to adapt". The Daily Illini.
  282. ^ Colb R (11 September 2022). "How Masking Changed My Experience of Being Deaf". The Atlantic.
  283. ^ "Masks saw more than 90 percent of deaf people struggle to communicate during pandemic, study finds". University of Essex. 3 October 2022.
  284. ^ "Transparent masks aid communication for hard of hearing". United Nations. Retrieved 19 November 2022.
  285. ^ Wright S (9 June 2020). "Five easy steps to get your dog used to face masks". Your Dog Magazine. Retrieved 24 July 2020.
  286. ^ a b Courtney-Guy S (24 July 2020). "People with disabilities fear abuse for not wearing face masks in public". Metro. Retrieved 24 July 2020.
  287. ^ a b Dwyer D (30 July 2020). "Few medical reasons for not wearing a face mask". ABC News.
  288. ^ "American College of Chest Physicians, American Lung Association, American Thoracic Society and COPD Foundation Statement on Importance of Patients with Chronic Lung Disease Wearing Facial Coverings". American Lung Association. 16 July 2020.
  289. ^ Brown M (16 July 2020). "Fact check: ADA does not provide blanket exemption from face mask requirements". USA Today.
  290. ^ Kamenetz A (28 January 2022). "After 2 years, growing calls to take masks off children in school". NPR. Retrieved 13 November 2022.
  291. ^ Hong J (15 February 2022). "Parents lose patience over school mask mandate". CalMatters. Retrieved 13 November 2022.
  292. ^ McKeever A (17 February 2022). "Do masks really harm kids? Here's what the science says". National Geographic. Archived from the original on 17 February 2022. Retrieved 13 November 2022.
  293. ^ "About 40% of parents think mask-wearing harmed their kids' school experience". Harvard University. 30 March 2022. Retrieved 13 November 2022.
  294. ^ Goldstein D (7 September 2022). "At Head Start, Masks Remain On, Despite C.D.C. Guidelines". The New York Times. Archived from the original on 2 October 2022. Retrieved 13 November 2022.
  295. ^ Thomson S (23 March 2022). "Mask mandates for children during the COVID-19 pandemic: an international human rights perspective". Scandinavian Journal of Public Health. 50 (6): 683–685. doi:10.1177/14034948221081087. PMID 35319288. S2CID 247615322.
  296. ^ "Health Experts Stress Need To Fight 'Mask Exhaustion', Continue To Follow COVID Safety Guidelines". CBS New York. 12 November 2020.
  297. ^ a b c Beswick E (14 July 2020). "Coronavirus: How the wearing of masks has exposed a divided Europe". euronews. See also Smith M (27 July 2020). "Face mask use surges after becoming compulsory in shops". YouGov.
  298. ^ Petersen MB, Lindholt MF, Jørgensen F. "Håndteringen af Coronaepidemien og Borgernes Adfærd, Tillid og Trivsel" (PDF). fm.dk (Danish Ministry of Finance). Institut for Statskundskab, Aarhus University. Archived from the original (PDF) on 16 September 2021. Retrieved 28 August 2021.
  299. ^ Ibbetson C (31 July 2020). "Should supermarkets challenge those shopping without masks?". YouGov.
  300. ^ Denworth L (14 May 2020). "Masks Reveal New Social Norms: What a Difference a Plague Makes". Scientific American.
  301. ^ a b Hutchins HJ, Wolff B, Leeb R, Ko JY, Odom E, Willey J, et al. (October 2020). "COVID-19 Mitigation Behaviors by Age Group - United States, April-June 2020". MMWR. Morbidity and Mortality Weekly Report. 69 (43): 1584–1590. doi:10.15585/mmwr.mm6943e4. PMC 7641002. PMID 33119562.
  302. ^ a b Tschorn A (22 June 2020). "Mask shaming men won't work. Here's what will". Los Angeles Times.
  303. ^ a b Srikanth A (14 May 2020). "Men less likely to wear face masks because they're 'not cool' and 'a sign of weakness' says study". The Hill.
  304. ^ Okten IO, Gollwitzer A, Oettingen G (2020). "Gender differences in preventing the spread of coronavirus". Behavioral Science & Policy. 6 (2): 109–122. doi:10.1353/bsp.2020.0022. S2CID 238608499.
  305. ^ Willingham E (29 June 2020). "The Condoms of the Face: Why Some Men Refuse to Wear Masks". Scientific American.
  306. ^ Wong B (23 July 2020). "The Psychology Behind Why Men Refuse To Wear Masks". HuffPost.
  307. ^ Howard MC (February 2021). "Gender, face mask perceptions, and face mask wearing: Are men being dangerous during the COVID-19 pandemic?". Personality and Individual Differences. 170: 110417. doi:10.1016/j.paid.2020.110417. PMC 7543707. PMID 33052155.
  308. ^ Rigby J, Satija B (8 May 2023). "WHO declares end to COVID global health emergency". Reuters. Retrieved 9 May 2023.
  309. ^ Pagliari C (17 June 2020). "What do world leaders really mean by refusing to wear face masks?". The University of Edinburgh.
  310. ^ Le Roux M (8 May 2020). "To mask or not to mask? World leaders scrutinised over face coverings". Agence France-Presse – via Yahoo! News.
  311. ^ Serhan Y (13 May 2020). "Lessons From Slovakia – Where Leaders Wear Masks". The Atlantic.
  312. ^ Smith S (10 August 2020). "Unmasked: How Trump's mixed messaging on face-coverings hurt U.S. coronavirus response". NBC News.
  313. ^ Madhani A (27 June 2020). "What to wear: Feds' mixed messages on masks sow confusion". AP News.
  314. ^ Blake A (27 October 2020). "GOP governors have overwhelmingly encouraged masks. Trump still resists them". The Washington Post.
  315. ^ Mackey R (12 July 2020). "Trump Manages to Wear a Mask and Undercut Mask-Wearing at the Same Time". The Intercept. Retrieved 14 November 2020.
  316. ^ Quinn M (12 July 2020). "Surgeon general says administration 'trying to correct' earlier guidance against wearing masks". CBS News.
  317. ^ Griffiths J (2 April 2020). "Asia may have been right about coronavirus and face masks, and the rest of the world is coming around". CNN.
  318. ^ Watterson A (17 April 2020). "Through all the misinformation, what is the truth of wearing face masks?". The National.
  319. ^ Frank TA (8 April 2020). ""I Was Looking at Them in the Wrong Way": Mask Misinformation and the Failure of the Elites". Vanity Fair.
  320. ^ a b Huo J (10 April 2020). "Why There Are So Many Different Guidelines For Face Masks For The Public". NPR.
  321. ^ "Coronavirus: Abrupt reversals on face mask policy raise new questions". France 24. 5 April 2020.
  322. ^ Walther M (4 April 2020). "The noble lie about masks and coronavirus should never have been told". The Week.
  323. ^ Tufekci Z (17 March 2020). "Why Telling People They Don't Need Masks Backfired". The New York Times.
  324. ^ Jankowicz M (15 June 2020). "Fauci said US government held off promoting face masks because it knew shortages were so bad that even doctors couldn't get enough". Business Insider.
  325. ^ Ross K (12 June 2020). "Dr. Fauci Explains Why Public Wasn't Told to Wear Masks When COVID-19 Pandemic Began". TheStreet.
  326. ^ Kelley A (16 June 2020). "Fauci: why the public wasn't told to wear masks when the coronavirus pandemic began". The Hill.
  327. ^ McArdle M (16 June 2020). "Fauci Confirms Public-Health Experts Downplayed Efficacy of Masks to Ensure They Would Be Available to Health-care Workers". National Review.
  328. ^ Novak M (17 June 2020). "Dr. Fauci Made the Coronavirus Pandemic Worse by Lying About Masks". Gizmodo.
  329. ^ a b c Aratani L (29 June 2020). "How did face masks become a political issue in America?". The Guardian.
  330. ^ a b c d Weissert W, Lemire J (7 May 2020). "Face masks make a political statement in era of coronavirus". AP News.
  331. ^ a b c Brewster J. "New Coronavirus Culture War: Some Republicans (Like Trump) Ditch Masks". Forbes. Retrieved 3 June 2020.
  332. ^ Walsh B (24 June 2020). "Polls show politics, not public health, drive Americans' attitudes toward coronavirus masks". Axios.
  333. ^ Pancevski B, Douglas J (29 June 2020). "Masks Could Help Stop Coronavirus. So Why Are They Still Controversial?". The Wall Street Journal.
  334. ^ a b Facciani M (9 September 2020). "Video: How did mask wearing become so politicized?". The Conversation.
  335. ^ a b c d Tu J (1 April 2020). "Taiwan challenges gender stereotypes with pink mask campaign". Women's Agenda. Retrieved 3 June 2020.
  336. ^ a b Picheta R (20 July 2020). "Hundreds of demonstrators, some wearing masks, protest against mask-wearing in London". CNN.
  337. ^ Beer T (16 July 2020). "Anti-Mask Rallies Continue In U.S. Amid Rising Coronavirus Cases And Deaths". Forbes.
  338. ^ a b Bogart N (20 July 2020). "Anti-mask rallies held across Canada despite increased support for mandatory masks". CTV News.
  339. ^ Smyth M (21 July 2020). "Don't get smug about the U.S. – coronavirus could come back to bite Canada, too". Global News.
  340. ^ Kaufman S (19 October 2020). "Violent Anti-Mask Protests Break Out In Czech Republic". Newsy.
  341. ^ Jap K (18 October 2020). "After the demonstration, the Old Town Square turned into a battlefield". Novinky.
  342. ^ Molteni M, Rogers A (2 July 2020). "How Masks Went From Don't-Wear to Must-Have During the Coronavirus Pandemic". Wired.
  343. ^ Rinkunas S (20 April 2020). ""My Body, My Choice" Doesn't Apply to Coronavirus". Vice.
  344. ^ "'My body, my choice': Sen. Chase defends maskless indoor campaign event". WTVR. 9 October 2020.
  345. ^ Beer T (24 June 2020). "'I Can't Breathe' Shouts Arizona Councilman Before Removing Mask At 'Anti-Mask' Rally". Forbes.
  346. ^ Parrish J (30 November 2020). "Downtown Boise businesses targeted by anti-mask protesters: A group of anti-mask protesters went into Boise businesses on Saturday to 'serve' them papers saying their mask policies were illegal". KTVB. Retrieved 5 December 2020.
  347. ^ Aratani L (29 June 2020). "How did face masks become a political issue in America?". The Guardian. Retrieved 16 January 2021.
  348. ^ Kane PL (29 April 2020). "The Anti-Mask League: lockdown protests draw parallels to 1918 pandemic". The Guardian. Retrieved 8 December 2020.
  349. ^ "Anti-Maskers Ready to Start Masking—to Protect Themselves From the Vaccinated". Vice. 11 May 2021. Retrieved 12 May 2021.
  350. ^ Hies O, Lewis MB (January 2022). "Beyond the beauty of occlusion: medical masks increase facial attractiveness more than other face coverings". Cognitive Research. 7 (1): 1. doi:10.1186/s41235-021-00351-9. PMC 8743690. PMID 35006366.
  351. ^ Steinbrecher L (25 June 2020). "Utah's faith leaders urge followers to wear masks in public". Fox News. Retrieved 6 August 2020.
  352. ^ Lennihan M (7 October 2020). "Faces meet fashion in New Yorkers' mask choices". AP News.
  353. ^ a b Sanoff R (7 April 2020). "Coronavirus couture: the rise of the $60 designer face mask". The Guardian.
  354. ^ Elan P (10 September 2020). "Face masks pick perilous path from health protector to fashion accessory". The Guardian.
  355. ^ Rabimov S (27 April 2020). "20 Fashion Brands Getting Most Creative With Coronavirus Face Masks". Forbes.
  356. ^ Sutton S (12 October 2020). "2020's Highly-Debated Outfit Trick Is Actually Extremely Popular". InStyle.
  357. ^ Williams S (16 May 2020). "Coronavirus: How face masks are becoming fashionable". BBC News.
  358. ^ Holland O, Ananda P (24 March 2020). "Fashion industry answers the call for masks and personal protective equipment to fight Covid-19". CNN.
  359. ^ Givhan R (5 May 2020). "Masks are here to stay. And they're quickly becoming a way to express ourselves". The Washington Post.
  360. ^ Parisi D (27 July 2020). "Fashion warms up to face masks as a new product category". Glossy.
  361. ^ a b Jana R (20 August 2020). "Are masks helping or hindering the fashion industry?". The Daily Telegraph.
  362. ^ Carreon J (10 August 2020). "Match Your Full Look to Your Face Mask, Because This Is How We Dress Now". Elle.
  363. ^ a b Besser R (22 May 2020). "Believe It or Not, There Is an Overarching Face Mask Trend". Vogue.
  364. ^ Sytas A (6 May 2020). "Lithuanian capital holds 'Mask Fashion Week' amid coronavirus pandemic". Reuters.
  365. ^ Puhak J (14 August 2020). "Disney releases uniform coronavirus face masks for theme park employees". Fox News.
  366. ^ Henderson C. "Disney debuts matching pixie dust masks for theme park employees". USA Today.
  367. ^ Laville S (18 November 2020). "53m discarded Covid face masks in UK 'could be polluting the sea'". The Guardian.
  368. ^ Bowyer C, Roberts KP, Kolstoe S, Fletcher S (14 August 2020). "Coronavirus face masks: an environmental disaster that might last generations". The Conversation.
  369. ^ Coronado L (24 October 2020). "Environmentalists Track Increase in Face Masks and Trash Since Pandemic". NBC 7 San Diego. Retrieved 20 November 2020.
  370. ^ Parashar N, Hait S (March 2021). "Plastics in the time of COVID-19 pandemic: Protector or polluter?". The Science of the Total Environment. 759: 144274. doi:10.1016/j.envc.2021.100039. PMC 7873601. PMID 33333331.
  371. ^ Khan J, Momin SA, Mariatti M, Vilay V, Todo M (November 2021). "Recent advancements in nonwoven bio-degradable facemasks to ameliorate the post-pandemic environmental impact". Materials Research Express. 8 (11): 112001. Bibcode:2021MRE.....8k2001K. doi:10.1088/2053-1591/ac35d0.
  372. ^ "BfArM - Empfehlungen des BfArM - Hinweise des BfArM zur Verwendung von Mund-Nasen-Bedeckungen, medizinischen Gesichtsmasken sowie partikelfiltrierenden Halbmasken (FFP-Masken)". Archived from the original on 16 April 2020. Retrieved 1 October 2021.
  373. ^ "Wort für Mund-Nasen-Schutz auf Saterfriesisch gesucht".
  374. ^ "Was heißt "Mund-Nasen-Schutz" auf Saterfriesisch?". ndr.de.
  375. ^ "Mund-Nasen-Schutz auf saterfriesisch: "Sküüldouk"". 13 January 2021.
  376. ^ "Wie heißt "Mund-Nasen-Schutz" auf Friesisch?". 14 May 2020.
  377. ^ "Wie heißt "Mund-Nasen-Schutz" auf Friesisch?". nordfriiskinstituut.eu. 14 May 2020.