CDC recognizes that coronavirus can be transmitted by air

THE Center for Disease Prevention and Control of the United States (CDC) recognized on Monday 5 that the new coronavirus can be transmitted by air. The US health agency has updated a document available on the agency’s website on ways to contaminate the SARS-CoV-2 with that information, but the World Health Organization (WHO) had already warned about this possibility in July.

In the guideline, the CDC notes that airborne transmission of COVID-19 can occur “sometimes” and “under certain conditions” by exposure to droplets or small particles of the virus that can remain in the air for minutes or hours. However, she says the infection is more common among people who have had close contact. The agency also says this type of spread is an important pathway in other infections, such as tuberculosis, measles and chickenpox.

“There is evidence that, under certain conditions, people with covid-19 appear to have infected others who were more than two meters away. These transmissions occurred in closed spaces with inadequate ventilation. Sometimes the infected person breathed with difficulty, for example, singing or exercising ”, he describes.

“Under these circumstances, scientists believe that the number of droplets and smaller infectious particles produced by people with COVID-19 were concentrated enough to transmit the virus to other people. The infected people were in the same space during the same period. period or shortly after leaving the person with covid-19 “, completes the CDC.

The page update comes after an incident last month, when the agency removed a post acknowledging the over-the-air broadcast. According to the agency, the material did not undergo a proper review and was published in error. The project text included a reference to aerosols – tiny droplets that can stay in the air, potentially traveling a significant distance. Authorities said the project was removed because they feared the language could be misinterpreted as a suggestion that airborne transmission is the main way the virus spreads.

In July, the WHO published a scientific report, after pressure from researchers, in which it began to consider the risk of transmission of the new coronavirus by air. Thereafter, the use of protective masks in closed environments is also recommended. At the time, the organization cited reports of outbreaks related to indoor venues, such as restaurants, religious temples, and gymnastics spaces.

Days earlier, the world body had received a letter signed by 239 scientists from 32 countries outlining evidence that smaller particles could infect people. With the document, they asked the agency to reevaluate the recommendations that had been repeated until then. This recognition would help define the most effective strategies and provide a clear and consistent guide to the public.

Also on Monday, American university scientists posted a joint letter on the magazine’s website. Sciences in which they affirm that “there is overwhelming evidence” that the inhalation of Sars-CoV-2 is the main route of transmission of covid-19 and, therefore, it is necessary to explain the difference between aerosols and droplets using the measure of length 100 µm (100 microns). According to them, this distinction “more effectively separates the aerodynamic behavior, the inhalation capacity and the effectiveness of the interventions”.

“Droplet viruses (larger than 100 µm) typically fall to the ground within seconds within two meters from the source and can be sprayed as small cannonballs onto nearby individuals. Due to their limited range of travel, physical distance reduces exposure to these droplets ”, they point out.

Aerosol viruses (less than 100 µm) “can remain suspended in the air for several seconds at a time, like smoke, and be inhaled. They are highly concentrated near an infected person, so they can infect those nearby “. However, they warn that these infectious virus-containing particles can also travel more than two meters and accumulate in the air in a poorly ventilated environment, leading to “spreading events.”

Scientists also explain that people with COVID-19 release thousands of virus-laden aerosols and fewer droplets when breathing or speaking. “So someone is much more likely to inhale aerosols than to be sprayed by a drop, and therefore the balance of attention needs to shift to protection against airborne transmission,” they say. For them, in addition to the need to wear a mask, social distance and hygiene measures, it is necessary for health professionals to give “clear guidelines on the importance of outdoor activities, improve indoor air through ventilation and filtration and improve protection. ” for high-risk workers. ” / With international agency