What is the novel coronavirus (COVID-19)?

This article was last reviewed and updated on April 28, 2021.

Coronavirus disease 2019 (COVID-19) is caused by a coronavirus called SARS-CoV-2. A coronavirus is a type of virus that causes respiratory tract infections, such as colds and pneumonia. Although coronaviruses usually cause mild symptoms, they can (on rare occasions) cause life-threatening breathing difficulties and death.

Where did the disease originate?

Coronaviruses are common among animals. They’re ‘zoonotic,’ meaning that they can be spread between humans and animals.The reservoir — where microbes such as viruses live and grow — for COVID-19 appears to be bats. Research into where the infection started is ongoing, but a major source of the outbreak has been traced to a large seafood and meat market in Wuhan City, China. Due to the ability of the virus to spread from person to person so easily, it has since been declared a pandemic.

How does COVID-19 spread?

COVID-19 mainly spreads through respiratory droplets produced when an infected person coughs or sneezes. Those droplets can be inhaled by people nearby, or transferred when someone touches their mouth, nose, or eyes with unwashed hands. You are at highest risk if you are in direct contact or physically close (within 6 feet) to someone that has COVID-19.

There is some evidence that some COVID-19 infections have been spread through small droplets and particles that have lingered in the air and infected people more than 6 feet away.

It is possible that touching a surface contaminated with respiratory droplets and then touching your mouth, nose or eyes is a way of acquiring the infection but is not a common way that COVID-19 is spread.1

The CDC recommends wearing a mask when you are around people not in your immediate household and in public settings. Masks protect the wearer as well as others they may come in contact with.