The U.S. Centers for Disease Control and Prevention has updated guidelines on its website that the coronavirus can often spread “through respiratory droplets or small particles, such as those in aerosols,” which are produced even when a person breathes.
“Airborne viruses, including COVID-19, are among the most contagious and easily spread,” the website said.
Earlier, the CDC website said that Covid-19 was thought to spread mainly between people in close contact – about 6 feet – and “through respiratory droplets produced when an infected person coughs, sneezes or talks.”
The page, updated on Friday, still says that Covid-19 is most commonly spread among people who are in close contact with each other, and now it is said that the virus is known to spread “through respiratory droplets or small particles, such as those in aerosols produced when an infected person coughs, sneezes, sings, speaks or breathes. “
These particles can cause infection by “inhalation into the nose, mouth, airways and lungs,” it is said. “This is thought to be the main way the virus spreads.”
“There is growing evidence that droplets and airborne particles can remain suspended in the air and inhaled by others, as well as travel distances of more than 6 feet (for example, during choral practice, in restaurants or in fitness classes),” now he says. “In general, an indoor environment without good ventilation increases this risk.”
The CDC has also added new measures to its information to protect itself and others.
Previously, the CDC offered to maintain a “good social distance” of about 6 feet, wash your hands, regularly clean and disinfect surfaces, and cover your mouth and nose with a mask when you are around others.
It now says “stay at least 6 feet away from others when possible” and continues to direct people to wear a mask and clean and disinfect regularly. But now it is also said that people should stay home and isolate themselves when they are sick and “use air purifiers to help reduce indoor air germs.”
Masks, he notes, should not replace other prevention measures.
The update also changed the language around asymptomatic transmission, moving from saying “some people without symptoms may be able to spread the virus” to “people who are infected but show no symptoms may spread the virus to others.”
Scientists have demanded recognition of air transmission
For months, scientists have been noting the possibility of transmitting coronavirus through viral particles in the air and urging health agencies to recognize it.
In April, a prestigious scientific panel said in a letter to the White House that research showed that the coronavirus could be spread not only by sneezing or coughing, but also simply by speaking or possibly even simply breathing.
“While the current [coronavirus] specific studies are limited, the results of the available studies are consistent with the aerosolization of the virus from normal respiration, “said in a letter written by Dr. Harvey Feinberg, former dean of the Harvard School of Public Health and chairman of the NAS Standing Committee on emerging infectious diseases and health threats in the 21st century.
“The research currently available supports the possibility that [coronavirus] it can be spread by bioaerosols generated directly from patients’ exhalation, “the letter said.
And in July, 239 scientists published a letter calling on the World Health Organization and other public health organizations to be more candid about the likelihood of people catching the virus from droplets floating in the air.
“Current guidelines from a number of international and national authorities focus on hand washing, maintaining social distance and droplet protection,” the researchers wrote in a letter published in the journal Clinical Infectious Diseases.
“Most public health organizations, including the World Health Organization, do not recognize airborne transmission, with the exception of aerosol generation procedures performed in health facilities. Hand washing and social distancing are appropriate, but in our opinion insufficient to provide protection. from virus carriers micro-droplets released into the air by infected people, “they added.
Following the publication of the letter, the WHO published a report detailing how the coronavirus could pass from one person to another, including by air during certain medical procedures and possibly by air in crowded interiors.
On Sunday, one of the letter’s lead authors, Donald Milton, a professor of environmental health at the University of Maryland who studies how viruses are transmitted, said the CDC’s new language was a “major improvement.”
“I’m very encouraged to see the CDC pay attention and move with science. The evidence is piling up,” Milton wrote in an email to CNN.
He described a pre-release paper released in August – in which scientists described the cultivation of a viable virus from air in a hospital – as “an important addition to reports of large outbreaks, apparently resulting from aerosol transmission traveling more than 6 feet”.
“It’s time for the WHO to recognize these advances in science,” Milton said.
Video: CDC Updates Asymptomatic Covid-19 Testing Guidelines (CNN)
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