The US agency has reiterated that the new coronavirus can be airborne, however, it maintains that it is not the main method of transmission. It is the third change of the CDC in less than 30 days.
For the third time in less than a month, the CDC changed guidelines on how Covid-19 spreads. The agency said on Monday that airborne transmission is possible, but that it is not the most common way for the virus to travel from person to person. That idea was already published and then removed from the organization’s website in September, according to NBC
The CDC updated its page on the spread of the virus on Monday to say that “some infections can be spread by exposure to the virus in small drops and particles that can remain in the air for minutes to hours.” These small droplets and particles, in turn, can infect people who are more than 6 feet [1m82] away “from the person who is infected or after that person has left the space”.
In September, the agency quietly altered its website to say that the coronavirus could spread through aerosols, which are tiny particles that can float in the air. But three days later, the expression was removed. The CDC justified that it was a “draft guideline” that had been published “by mistake”.
On Monday, the CDC issued a statement on the latest set of transmission guidelines, acknowledging “the existence of some published reports that show limited and unusual circumstances in which people with Covid-19 infected others who were more than 6 feet away away or just after a Covid-19 positive person left the area. “
“In these cases,” says the statement, “the transmission occurred in closed, poorly ventilated spaces, which often involved activities that caused heavier breathing, such as singing or exercising”.
Covid-19 “spreads easily from person to person,” says the CDC website, most commonly within 2 meters of another person, especially when an infected person coughs, sneezes, sings, talks or even breathes.
The CDC also said that it is possible for a person to be infected by touching a contaminated surface and then touching his or her mouth, eyes or nose, but that it is a much less common method of transmission.
Joseph Allen, associate professor in the Harvard T.H. Chan School of Public Health, said it is time for the CDC to make these changes in relation to air transmission.
“This is exactly what we have been saying for many months … that a viable infectious virus can travel beyond six feet,” said Allen. “If you are indoors with someone who is spreading viruses and there is little ventilation, well, viral particles can build up in the room. And then 1m80 is not as protective.”
“The term airborne is not to be feared, it just means that we have to take some extra precautions,” he said. This includes increasing ventilation and air filtration indoors, as well as continuing to wear a mask, washing hands and maintaining social distance
