What is the common cold?

Although “the common cold” is typically treated like a single condition, it’s actually a generic term for mild upper respiratory tract infections caused by viruses (such as rhinovirus, respiratory syncytial virus, human metapneumovirus, and non-COVID coronavirus, to name a few). It’s one of the most common illnesses in the world — adults will get 2–3 colds each year, on average, and children can get many more.^{[1] [2]}