Today, October 5, 2020, the Centers for Disease Control and Prevention (CDC) issued updated guidance to its How COVID-19 Spreads website, which includes information about the potential for airborne spread of the virus that causes COVID-19.

CDC continues to believe, based on current science, that people are more likely to become infected the longer and closer they are to a person with COVID-19. Today’s update acknowledges the existence of some published reports showing limited, uncommon circumstances where people with COVID-19 infected others who were more than 6 feet away or shortly after the COVID-19-positive person left an area. In these instances, transmission occurred in poorly ventilated and enclosed spaces that often involved activities that caused heavier breathing, like singing or exercise. Such environments and activities may contribute to the buildup of virus-carrying particles.

Airborne transmission

Some infections can be spread by exposure to virus in small droplets and particles that can linger in the air for minutes to hours. These viruses may be able to infect people who are further than 6 feet away from the person who is infected or after that person has left the space.

This kind of spread is referred to as airborne transmission and is an important way that infections like tuberculosis, measles, and chicken pox are spread.

There is evidence that under certain conditions, people with COVID-19 seem to have infected others who were more than 6 feet away. These transmissions occurred within enclosed spaces that had inadequate ventilation. Sometimes the infected person was breathing heavily, for example while singing or exercising.

Under these circumstances, scientists believe that the amount of infectious smaller droplet and particles produced by the people with COVID-19 became concentrated enough to spread the virus to other people. The people who were infected were in the same space during the same time or shortly after the person with COVID-19 had left.

Available data indicate that it is much more common for the virus that causes COVID-19 to spread through close contact with a person who has COVID-19 than through airborne transmission.

Recommendations

CDC’s recommendations remain the same based on existing science and after a thorough technical review of the guidance.

People can protect themselves from the virus that causes COVID-19 by staying at least 6 feet away from others, wearing a mask that covers their nose and mouth, washing their hands frequently, cleaning touched surfaces often and staying home when sick.