By Erika Edwards - NBC News
For the third time in less than a month, the Centers for Disease Control and Prevention (CDC) has revised its guidance on how COVID-19 spreads.
The agency said on Monday that airborne transmission is possible, but that it is not the most common way in which the virus travels from person to person, a position it already made public in September although it was later deleted from its website.
The CDC on Monday updated its site on the spread of the virus, stating that "some infections can be spread by exposure to the virus in tiny droplets and particles that
can remain in the air for minutes or hours
."
[CDC Stumbles Again: Rectifying Guidance on How Coronavirus Is Spread, Claiming It Was Posted by Mistake]
Those tiny droplets and particles, in turn, can infect people who are more than six feet (1.82 meters) "from the person who is infected or after that person has left the space" in question. .
In September, the agency inadvertently changed its page, saying the coronavirus could spread through aerosols, which are tiny particles capable of floating in the air.
But three days later, this assertion
was removed
.
The CDC then claimed that it was a "draft guidance" that had been published "by mistake."
[Transmission of COVID-19 by air is only a small part of the way it spreads]
On Monday, the CDC issued a note on the latest set of transmission guidelines, acknowledging "the existence of some published reports showing limited and unusual circumstances in which people with COVID-19 infected others who were at more than six feet away or shortly after the COVID-19 positive person had left a "specified area.
"In these cases," the statement added, "the transmission occurred in
closed and poorly ventilated spaces
where activities that required more intense breathing, such as singing or exercising, were often performed."
Covid-19 "spreads very easily from person to person," says the CDC website, most commonly within a distance of up to 6 feet from another person, especially when an infected person
coughs, sneezes, sings, speaks or even breathe
.
The CDC also said that it is possible for a person to become infected by touching a contaminated surface and then touching their mouth, eyes or nose, but that it is a much less common method of transmission.
[WHO retracts after saying that asymptomatic people have a "low risk" of spreading COVID-19]
Joseph Allen, associate professor in the department of environmental health at Harvard TH Chan School of Public Health, said "it was about time" the CDC made these changes regarding airborne transmission.
"This is exactly what we have been saying for many months ... that an infectious virus capable of surviving in the environment
can travel beyond six feet
," Allen said.
"If you are indoors with someone who is spreading the virus and there is poor ventilation, well, the virus particles can accumulate in the room. And then six feet is not so protective."
"The term airborne is not to be feared, it just means that we have to take some extra precautions," he said.
These include increasing ventilation and air filtration indoors, as well as maintaining the use of face masks, washing hands, and respecting social distance.
