COVID-19 is thought to spread mainly through close contact from person to person, including between people who are physically near each other (within about 6 feet). People who are infected but do not show symptoms can also spread the virus to others. Cases of reinfection with COVID-19 have been reported but are rare. We are still learning about how the virus spreads and the severity of illness it causes.
How easily a virus spreads from person to person can vary. The virus that causes COVID-19 appears to spread more efficiently than influenza but not as efficiently as measles, which is among the most contagious viruses known to affect people.
Respiratory droplets can also land on surfaces and objects. It is possible that a person could get COVID-19 by touching a surface or object that has the virus on it and then touching their own mouth, nose, or eyes.
Spread from touching surfaces is not thought to be a common way that COVID-19 spreads
It appears that the virus that causes COVID-19 can spread from people to animals in some situations. CDC is aware of a small number of pets worldwide, including cats and dogs, reported to be infected with the virus that causes COVID-19, mostly after close contact with people with COVID-19.
Learn what you should do if you have pets.
Currently, the risk of COVID-19 spreading from animals to people is low. Learn about COVID-19 and pets and other animals.
The best way to prevent illness is to avoid being exposed to this virus. You can take steps to slow the spread.
Information about the characteristics of these variants is rapidly emerging. Scientists are working to learn more about how easily they spread, whether they could cause more severe illness, and whether currently authorized vaccines will protect people against them.
Viruses constantly change through mutation, and new variants of a virus are expected to occur over time. Sometimes new variants emerge and disappear. Other times, new variants emerge and persist. Multiple variants of the virus that causes COVID-19 have been documented in the United States and globally during this pandemic.
The virus that causes COVID-19 is a type of coronavirus, a large family of viruses. Coronaviruses are named for the crown-like spikes on their surfaces. Scientists monitor changes in the virus, including changes to the spikes on the surface of the virus. These studies, including genetic analyses of the virus, are helping scientists understand how changes to the virus might affect how it spreads and what happens to people who are infected with it.
Multiple variants of the virus that causes COVID-19 are circulating globally:
Scientists are working to learn more about these variants, and more studies are needed to understand:
Public health officials are studying these variants quickly to learn more to control their spread. They want to understand whether the variants:
CDC, in collaboration with other public health agencies, is monitoring the situation closely. CDC is working to monitor the spread of identified variants, characterize emerging viral variants, and expand its ability to find new SARS-CoV-2 variants. CDC is collaborating with EPA to confirm that disinfectants on EPA's List N: Disinfectants for Coronavirus inactivate these variant viruses. As new information becomes available, CDC will provide updates.
Air travel requires spending time in security lines and airport terminals, which can bring you in close contact with other people and frequently touched surfaces. Social distancing is difficult in busy airports and on crowded flights, and sitting within 6 feet of others, sometimes for hours, may increase your risk of getting COVID-19. How you get to and from the airport, such as with public transportation and ridesharing, can also increase your chances of being exposed to the virus.
Testing before and after travel can reduce the risk of spreading COVID-19. Testing does not eliminate all risk, but when paired with a period of staying at home and everyday precautions like wearing masks and social distancing, it can make travel safer by reducing spread on planes, in airports, and at destinations.
Here is what to know:
Below is what you need to know about getting tested before your international flight.