The common cold is an upper respiratory tract disease that mainly affects the nose, and sometimes the throat, larynx and sinuses. Over 200 viruses can cause colds, most commonly rhinoviruses but also coronaviruses, influenza viruses, adenoviruses and others. Adults catch an average of 2–3 colds a year and children 6–8, making it the most common infectious human disease. The economic costs are huge, with colds responsible for 40% of time lost from work in the U.S. Colds are described in the Egyptian Ebers papyrus, the oldest surviving medical text, written before the 16th century BCE.
Symptoms include cough, sore throat, runny nose, nasal congestion, sneezing and sometimes muscle aches and headache; fever is common in young children. Symptoms typically resolve in 7–10 days, although some can last up to 3 weeks. The immune response to infection, rather than tissue destruction by the virus, causes most of the symptoms. Transmission occurs via airborne droplets and by contact with nasal secretions or contaminated objects. The viruses that cause colds can survive for prolonged periods in the environment (over 18 hours for rhinoviruses). Hand washing can help to prevent spread. No effective antiviral treatment or vaccine currently exists.