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Vaccines and autism

(Redirected from Link between vaccines and autism)

Extensive investigation into vaccines and autism spectrum disorder[1] has shown that there is no relationship between the two, causal or otherwise,[1][2][3] and that vaccine ingredients do not cause autism.[4] The American scientist Peter Hotez researched the growth of the false claim and concluded that its spread originated with Andrew Wakefield's fraudulent 1998 paper, and that no prior paper supports a link.[5]

Despite the scientific consensus for the absence of a relationship[1][2] and the retracted paper, the anti-vaccination movement at large continues to promote theories linking the two.[6] A developing tactic appears to be the "promotion of irrelevant research [as] an active aggregation of several questionable or peripherally related research studies in an attempt to justify the science underlying a questionable claim."[7]

Claimed mechanisms

See also: Causes of autism § Vaccines

The claimed mechanisms have changed over time, in response to evidence refuting each in turn.[8]

Vaccine-derived measles virus

See also: MMR vaccine and autism and Lancet MMR autism fraud

The idea of a link between the MMR vaccine and autism came to prominence after the publication of a paper by Andrew Wakefield and others in The Lancet in 1998. This paper, which was retracted in 2010 and whose publication led to Wakefield being struck off the United Kingdom medical register, has been described as "the most damaging medical hoax of the last 100 years".[9]

Wakefield's primary claim was that he had isolated evidence of vaccine-strain measles virus RNA in the intestines of autistic children, leading to a condition he termed autistic enterocolitis (a condition never recognised or adopted by the scientific community). This finding was later shown to be due to errors made by the laboratory where the polymerase chain reaction (PCR) tests were performed.[citation needed]

The Centers for Disease Control and Prevention (CDC),[10] the IOM of the United States National Academy of Sciences,[11] and the National Health Service[12] have all concluded that there is no link between the MMR vaccine and autism. A systematic review by the Cochrane Library concluded that there is no credible link between the MMR vaccine and autism, that the MMR vaccine has prevented diseases that still carry a heavy burden of death and complications, that the lack of confidence in the MMR vaccine has damaged public health, and that the design and reporting of safety outcomes in MMR vaccine studies are largely inadequate.[13]

In 2009, The Sunday Times reported that Wakefield had manipulated patient data and misreported results in his 1998 paper, thus falsifying a link with autism.[14] A 2011 article in the British Medical Journal describes the way in which Wakefield manipulated the data in his study in order to arrive at his predetermined conclusion.[15] An accompanying editorial in the same journal described Wakefield's work as an "elaborate fraud" which led to lower vaccination rates, putting hundreds of thousands of children at risk and diverting funding and other resources from research into the true cause of autism.[16]

On 12 February 2009, a special court convened in the United States to review claims under its National Vaccine Injury Compensation Program ruled that parents of autistic children are not entitled to compensation in their contention that certain vaccines caused their children to develop autism.[17]

Thiomersal

Main article: Thiomersal and vaccines

Thiomersal is an antifungal preservative used in small amounts in some multi-dose vaccines (where the same vial is opened and used for multiple patients) to prevent contamination of the vaccine.[18] Thiomersal contains ethylmercury, a mercury compound which is related to, but significantly less toxic than, the neurotoxic pollutant methylmercury. Despite decades of safe use,[19] public campaigns prompted the CDC and the American Academy of Pediatrics (AAP) to request vaccine makers to remove thiomersal from vaccines as quickly as possible on the precautionary principle. Thiomersal is now absent from all common United States and European Union vaccines, except for some preparations of influenza vaccine.[20] (Trace amounts remain in some vaccines due to production processes, at an approximate maximum of 1 microgramme, around 15% of the average daily mercury intake in the US for adults and 2.5% of the daily level considered tolerable by the World Health Organization [WHO].)[21][22] The action engendered concern thiomersal could have been responsible for autism.[20]

The idea that thiomersal was a cause or trigger for autism is now considered disproven, as incidence rates for autism increased steadily even after thiomersal was removed from childhood vaccines.[8] There is no accepted scientific evidence that exposure to thiomersal is a factor in causing autism.[23]

Under the U.S. Food and Drug Administration (FDA) Modernization Act (FDAMA) of 1997, the FDA conducted a comprehensive review of the use of thiomersal in childhood vaccines. Conducted in 1999, this review found no evidence of harm from the use of thiomersal as a vaccine preservative, other than local hypersensitivity reactions.[24] Despite this, starting in 2000, parents in the United States pursued legal compensation from a federal fund arguing that thiomersal caused autism in their children.[25] A 2004 Institute of Medicine (IOM) committee favored rejecting any causal relationship between autism and vaccines containing thiomersal[11] and rulings from the vaccine court in three test claims in 2010 established the precedent that thiomersal is not considered a cause of autism.[26][27][28]

Vaccine overload

Further information: Vaccine hesitancy § Vaccine overload

Following the belief that individual vaccines caused autism was the idea of vaccine overload, which claims that too many vaccines at once may overwhelm or weaken a child's immune system and lead to adverse effects.[29] Vaccine overload became popular after the Vaccine Injury Compensation Program in the United States accepted the case of nine-year-old Hannah Poling. Poling had encephalopathy, putting her on the autism spectrum disorder, which was believed to have worsened after getting multiple vaccines at nineteen months old.[8] There have been multiple cases reported similar to this one, which led to the belief that vaccine overload caused autism. However, scientific studies show that vaccines do not overwhelm the immune system.[8] In fact, conservative estimates predict that the immune system can respond to thousands of viruses simultaneously.[8] It is known that vaccines constitute only a tiny fraction of the pathogens already naturally encountered by a child in a typical year.[8] Common fevers and middle ear infections pose a much greater challenge to the immune system than vaccines do.[30] Other scientific findings support the idea that vaccinations, and even multiple concurrent vaccinations, do not weaken the immune system[8] or compromise overall immunity[31] and evidence that autism has any immune-mediated pathophysiology has still not been found.[8]

Aluminium salts

As mercury compounds in vaccines have been definitively ruled out as a cause of autism, some anti-vaccine activists propose aluminium salts as the cause of autism.[32] This is based in part on the erroneous popular belief that aluminium salts cause Alzheimer disease.[33] There is no substantial scientific evidence that aluminium salts are linked to autism but anti-vaccination activists commonly cite a number of papers which claim that there is in fact a link.[34] These are mainly published in predatory open access journals,[35] where peer-review is virtually non-existent. Work conducted by Christopher Shaw, Christopher Exley and Lucija Tomljenovic has been funded by the anti-vaccination Dwoskin Family Foundation.[36] The work published by Shaw et al. has been discredited by the World Health Organization.[37]

Celebrity involvement

 
Jenny McCarthy speaking against the use of vaccines. She remains convinced that they caused autism in her son.

Some celebrities have spoken out on their views that autism is related to vaccination, including: Jenny McCarthy, Kristin Cavallari,[38] Robert De Niro,[39] Jim Carrey,[40] Bill Maher,[41] and Pete Evans.[42]

McCarthy, one of the most outspoken celebrities on the topic, has said her son Evan's autism diagnosis was a result of the MMR vaccine.[43] She authored Louder than Words: A Mother's Journey in Healing Autism and co-authored Healing and Preventing Autism.[44] She also founded Generation Rescue, an organisation which provides resources for families affected by autism.[45]

In a September 2015 U.S. presidential debate, Republican Party candidate and future United States President Donald Trump stated he knew of a 2-year-old child who had recently received a combined vaccine, developed a fever, and subsequently autism.[46]

Robert F. Kennedy, Jr. is one of the most notable proponents of the anti-vaccine movement. Kennedy published the book Thimerosal: Let the Science Speak: The Evidence Supporting the Immediate Removal of Mercury--A Known Neurotoxin--From Vaccines.[47] He is also chairman of the board of Children's Health Defense, a group and website widely known for its anti-vaccination stance.[48]

Public opinion

In December 2020, a poll of 1,115 U.S. adults found 12% of respondents believed there is evidence vaccinations cause autism; 51% believed there is no evidence; and 37% did not know.[49]

An updated survey, conducted in March of 2023, concluded that adults think the MMR health benefits are high/very high, at 72%, and the risk of side effects is low/very low, at 64%.[50] There has also been a drop from 2019 in United States adults who believe students in schools should be fully vaccinated. The 2023 survey showed that a decrease to 70% of U.S. adults agree that children should be vaccinated for school but an increase to 28% believe that it is the parent's right to choose if the child is vaccinated for school.[50]

References

  1. ^ a b c Taylor LE, Swerdfeger AL, Eslick GD (June 2014). "Vaccines are not associated with autism: an evidence-based meta-analysis of case-control and cohort studies". Vaccine. 32 (29): 3623–9. doi:10.1016/j.vaccine.2014.04.085. PMID 24814559.
  2. ^ a b Bonhoeffer J, Heininger U (June 2007). "Adverse events following immunization: perception and evidence" (PDF). Current Opinion in Infectious Diseases. 20 (3): 237–46. doi:10.1097/QCO.0b013e32811ebfb0. PMID 17471032. S2CID 40669829.
  3. ^ Boseley S (February 2, 2010). "Lancet retracts 'utterly false' MMR paper". The Guardian. Retrieved February 2, 2010.
  4. ^ "Vaccines Do Not Cause Autism Concerns". Centers for Disease Control and Prevention. 2018-12-12. Retrieved 2019-02-07.
  5. ^ Peter J., Hotez (30 October 2018). "Vaccines Did Not Cause Rachel's Autism: My Journey as a Vaccine Scientist, Pediatrician, and Autism Dad". JHU Press. ISBN 9781421426600. OCLC 1020295646.
  6. ^ Cummins, Eleanor (February 2019). "How autism myths came to fuel anti-vaccination movements A timeline leading to the 2019 measles outbreaks". Popular Science.
  7. ^ Foster CA, Ortiz SM (February 2016). "Vaccines, Autism, and the Promotion of Irrelevant Research: A Science-Pseudoscience Analysis". Skeptical Inquirer. 41 (3): 44–48. Archived from the original on 2018-10-06. Retrieved 6 October 2018.
  8. ^ a b c d e f g h Gerber JS, Offit PA (February 2009). "Vaccines and autism: a tale of shifting hypotheses". Clinical Infectious Diseases. 48 (4): 456–61. doi:10.1086/596476. PMC 2908388. PMID 19128068.
  9. ^ Flaherty DK (October 2011). "The vaccine-autism connection: a public health crisis caused by unethical medical practices and fraudulent science". The Annals of Pharmacotherapy. 45 (10): 1302–4. doi:10.1345/aph.1Q318. PMID 21917556. S2CID 39479569.
  10. ^ "Concerns about autism". Centers for Disease Control and Prevention. 2010-01-15.
  11. ^ a b Immunization Safety Review Committee (2004). Immunization Safety Review: Vaccines and Autism. The National Academies Press. doi:10.17226/10997. ISBN 978-0-309-09237-1. PMID 20669467.
  12. ^ MMR Fact Sheet Archived June 15, 2007, at the Wayback Machine, from the United Kingdom National Health Service. Retrieved June 13, 2007.
  13. ^ Di Pietrantonj, Carlo; Rivetti, Alessandro; Marchione, Pasquale; Debalini, Maria Grazia; Demicheli, Vittorio (20 April 2020). "Vaccines for measles, mumps, rubella, and varicella in children". The Cochrane Database of Systematic Reviews. 4 (4): CD004407. doi:10.1002/14651858.CD004407.pub4. ISSN 1469-493X. PMC 7169657. PMID 32309885.
  14. ^ Deer B (2009-02-08). "MMR doctor Andrew Wakefield fixed data on autism". Sunday Times. Archived from the original on May 25, 2010. Retrieved 2009-02-09.
  15. ^ Deer B (January 2011). "How the case against the MMR vaccine was fixed". BMJ. 342: c5347. doi:10.1136/bmj.c5347. PMID 21209059. S2CID 46683674.
  16. ^ Godlee F, Smith J, Marcovitch H (January 2011). "Wakefield's article linking MMR vaccine and autism was fraudulent". BMJ. 342: c7452. doi:10.1136/bmj.c7452. PMID 21209060. S2CID 43640126.
  17. ^ Vaccine court and autism:
    • "Vaccine didn't cause autism, court rules". CNN. 2009-02-12. Retrieved 2009-02-12.
    • Theresa Cedillo and Michael Cedillo, as parents and natural guardians of Michelle Cedillo vs. Secretary of Health and Human Services, 98-916V (United States Court of Federal Claims 2009-02-12).
  18. ^ Baker JP (February 2008). "Mercury, vaccines, and autism: one controversy, three histories". American Journal of Public Health. 98 (2): 244–53. doi:10.2105/AJPH.2007.113159. PMC 2376879. PMID 18172138.
  19. ^ "Thimerosal in Vaccines". Centers for Disease Control and Prevention. 2019-01-24. Retrieved 2019-02-07.
  20. ^ a b Offit PA (September 2007). "Thimerosal and vaccines--a cautionary tale". The New England Journal of Medicine. 357 (13): 1278–9. doi:10.1056/NEJMp078187. PMID 17898096.
  21. ^ Bose-O'Reilly S, McCarty KM, Steckling N, Lettmeier B (September 2010). "Mercury exposure and children's health". Current Problems in Pediatric and Adolescent Health Care. 40 (8): 186–215. doi:10.1016/j.cppeds.2010.07.002. PMC 3096006. PMID 20816346.
  22. ^ "Vaccine Safety & Availability – Thimerosal in Vaccines". FDA. 5 April 2019.
  23. ^ Doja A, Roberts W (November 2006). "Immunizations and autism: a review of the literature". The Canadian Journal of Neurological Sciences. 33 (4): 341–6. doi:10.1017/s031716710000528x. PMID 17168158.
  24. ^ "Vaccine Safety & Availability - Thimerosal in Vaccines". www.fda.gov. Retrieved 2016-02-08.
  25. ^ Sugarman SD (September 2007). "Cases in vaccine court--legal battles over vaccines and autism". The New England Journal of Medicine. 357 (13): 1275–7. doi:10.1056/NEJMp078168. PMID 17898095.
  26. ^ "UPDATE 1-US court rules again against vaccine-autism claims". Reuters. 2010-03-12. Retrieved 2019-02-07.
  27. ^ Salzberg, Steven. "Vaccine Court Ruling: Thimerosal Does Not Cause Autism". Retrieved 2019-02-07.
  28. ^ Dyer, Clare (2010-03-16). "Thiomersal does not cause autism, US court finds". BMJ. 340: c1518. doi:10.1136/bmj.c1518. PMID 20233774. S2CID 27129014. Retrieved 2019-02-07.
  29. ^ Hilton S, Petticrew M, Hunt K (May 2006). "'Combined vaccines are like a sudden onslaught to the body's immune system': parental concerns about vaccine 'overload' and 'immune-vulnerability'". Vaccine. 24 (20): 4321–7. doi:10.1016/j.vaccine.2006.03.003. PMID 16581162.
  30. ^ Immune challenges:
  31. ^ Vaccine burden:
  32. ^ Nerd, Gid M.-K; Health (2017-12-05). "Vaccines Don't Cause Autism". Retrieved 2019-02-07.{{cite news}}: CS1 maint: multiple names: authors list (link)
  33. ^ Lidsky TI (May 2014). "Is the Aluminum Hypothesis dead?". Journal of Occupational and Environmental Medicine. 56 (5 Suppl): S73-9. doi:10.1097/JOM.0000000000000063. PMC 4131942. PMID 24806729.
  34. ^ Principi, N; Esposito, S (September 2018). "Aluminum in vaccines: Does it create a safety problem?". Vaccine. 36 (39): 5825–31. doi:10.1016/j.vaccine.2018.08.036. PMID 30139653. S2CID 52073320.
  35. ^ "Vaccines, Autism, and Retraction". 2017-05-10. Archived from the original on 2019-10-19. Retrieved 2019-02-07.
  36. ^ "Dwoskin Foundation – Science-Based Medicine". Retrieved 2019-02-07.
  37. ^ "UBC stands behind vaccine studies discredited by WHO". 2015-03-04. Retrieved 2019-02-07.
  38. ^ "Kristin Cavallari Defends Anti-Vaccine Stance". The Huffington Post. 19 March 2014. Retrieved 2016-02-08.
  39. ^ "Robert De Niro defends discredited idea linking vaccines to autism". Stat. 13 April 2016. Retrieved 2016-04-13.
  40. ^ Kluger J (2 July 2015). "Jim Carrey, Please Shut Up About Vaccines". TIME.com. Retrieved 2016-02-08.
  41. ^ Tenbarge, Kat. "Bill Maher agreed with a controversial doctor, repeating a debunked theory that it was 'realistic' that vaccines have caused autism in children". Insider. Retrieved 2019-11-02.
  42. ^ "Bent Spoon to celebrity chef Pete Evans – Australian Skeptics Inc". 2019-03-28. Archived from the original on 2019-03-28. Retrieved 2021-01-26.
  43. ^ "Jenny McCarthy: "We're Not An Anti-Vaccine Movement ... We're Pro-Safe Vaccine"". FRONTLINE. Retrieved 2016-02-08.
  44. ^ Kluger J (2009-04-01). "Jenny McCarthy on Autism and Vaccines". Time. ISSN 0040-781X. Retrieved 2016-02-08.
  45. ^ "About Generation Rescue » Generation Rescue | Jenny McCarthy's Autism Organization". www.generationrescue.org. Retrieved 2016-02-08.
  46. ^ "Medical experts condemn Donald Trump for debate comments suggesting vaccines can cause autism". NY Daily News. 18 September 2015. Retrieved 2016-02-08.
  47. ^ Hyman M, Herbert MR (2014-08-04). Kennedy RF (ed.). Thimerosal: Let the Science Speak: The Evidence Supporting the Immediate Removal of Mercury--a Known Neurotoxin--from Vaccines. Skyhorse Publishing. ISBN 9781632206015.
  48. ^ Smith, Michelle R; Reiss, Johnatan (May 13, 2021). "Inside one network cashing in on vaccine disinformation". Associated Press. AP News. Retrieved October 3, 2021.
  49. ^ Even If It's 'Bonkers,' Poll Finds Many Believe QAnon And Other Conspiracy Theories
  50. ^ a b Pasquini, Cary Funk, Alec Tyson, Brian Kennedy and Giancarlo (2023-05-16). "Americans' Largely Positive Views of Childhood Vaccines Hold Steady". Pew Research Center. Retrieved 2024-09-26.{{cite web}}: CS1 maint: multiple names: authors list (link)
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