- The CDC has finally confirmed the worst thing about the novel coronavirus.
- COVID-19 can be spread from person to person through the air in aerosols, which is something the CDC had not formally admitted.
- This increases the risk of infection indoors because the virus can linger in the air for a longer time and travel distances much farther than 6 feet.
The CDC posted coronavirus guidance on its website a few days ago that finally addresses one of the worst things about the novel pathogen. The virus is airborne, which means it can spread via aerosols rather than just saliva droplets. But the CDC quickly pulled the updated guidance saying that a draft of the document was posted as an error. The WHO acknowledged the risk of COVID-19 aerosol transmission after being bombarded by 239 scientists demanding that aerosol spread be acknowledged. But the WHO still says the main way the virus spreads is via droplets.
After pulling it back the first time, the CDC has finally released the coronavirus guidance revision that acknowledges the virus spreads by airborne transmission. Still, the agency has crafted its message in a vague manner similar to the WHO.
When we sneeze and cough, we eject saliva droplets that may be invisible to the naked eye. They’re propelled into the air and can land on surfaces up to about 6 feet away. These droplets can contain active SARS-CoV-2, the virus that causes the COVID-19. If those droplets are inhaled by others, or reach their mouth, nose, or eyes via touch, it could lead to an infection.
But an increasing amount of research indicates that infected people eject even smaller droplets. The microdroplets can come out of your mouth even when speaking or just breathing. They contain a more limited amount of water that evaporates faster, and the microdroplets left behind turn into aerosols. They can linger in the air for a longer period of time than the heavier droplets that generally drop due to gravity. And they can travel beyond the 6-foot safe distance that the CDC and WHO recommend for social distancing. Aerosols containing active coronavirus can indeed infect others, and now the CDC has finally acknowledged it.
Face masks and social distancing can help mitigate the risk of both droplets and aerosol transmission, thereby reducing infection rates. No barrier is perfect, however, and infection is still possible. But masks might also help block the virus from being inhaled inside a poorly ventilated indoor area. Proper ventilation can help dissipate aerosols faster.
The CDC now addresses these COVID-19 aerosol transmission risks on its website, as follows:
COVID-19 can sometimes be spread by 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.
Separately, a team of scientists took it upon themselves to provide more information about coronavirus aerosol transmission, and that documentation is available online on Google Docs. It’s also being updated continuously with new information.