SARS-CoV-2, the virus that causes COVID-19, is spread from person to person through respiratory droplets or particles when infected people cough, sneeze, talk or breathe.
Most often, transmission occurs when such droplets or particles are breathed in or land in or on a person’s eyes, nose or mouth. As a result, risk is thought to be highest when people are in close contact with one another, typically within 6 feet or so of an infected person, according to the Centers for Disease Control and Prevention.
Especially in places with poor ventilation, however, SARS-CoV-2 can be spread through small respiratory particles that linger in the air and can reach those who are further than 6 feet away. Such airborne transmissions have occurred in enclosed spaces without adequate ventilation and have often involved exercising, shouting or singing by an infected person. “Prolonged exposure to these conditions, typically more than 15 minutes,” the CDC says, raises the risk of such spread.
While it is possible for someone to be infected by touching a contaminated surface, the agency says the risk “is generally considered to be low.”
People who are infected with the coronavirus but don’t have symptoms can still spread the virus. Although vaccination reduces the risk of viral transmission, it doesn’t eliminate it — which may be especially true with the highly transmissible omicron variant.
The CDC, for example, “expects that anyone with Omicron infection can spread the virus to others, even if they are vaccinated or don’t have symptoms.”