A coronavirus is a kind of common virus that causes an infection in your nose, sinuses, or upper throat. Most coronaviruses are not dangerous.

Some types of them are serious, though. About 858 people have died from Middle East respiratory syndrome (MERS), which first appeared in 2012 in Saudi Arabia and then in other countries in the Middle East, Africa, Asia, and Europe.

But in early January 2020, the World Health Organization identified a new type: 2019 novel coronavirus (2019-nCoV) in China. By late January, there were 300 confirmed cases in China and a death count that was still in the single digits, but rising. And despite airport screenings, a traveler had brought the first case to the U.S.

What Is a Coronavirus?
Coronaviruses were first identified in the 1960s, but we don’t know where they come from. They get their name from their crown-like shape. Sometimes, but not often, a coronavirus can infect both animals and humans.

Most coronaviruses spread the same way other cold-causing viruses do: through infected people coughing and sneezing, by touching an infected person’s hands or face, or by touching things such as doorknobs that infected people have touched.

Almost everyone gets a coronavirus infection at least once in their life, most likely as a young child. In the United States, coronaviruses are more common in the fall and winter, but anyone can come down with a coronavirus infection at any time.