The update comes on the heels of an embarrassing incident last month when the agency removed a draft that had not been properly reviewed and was published in error. The draft included a reference to an aerosol – tiny droplets that could remain in the air and potentially travel a great distance. Officials said the draft was removed because they feared the language would be misinterpreted as indicating that transmission of the virus is the main way the virus spreads.
This is not the case. The Centers for Disease Control and Prevention said the main drivers for the spread of the virus are larger respiratory droplets that are released when someone coughs, sneezes, sings, speaks or breathes.
The updated webpage states that under certain circumstances, people with COVID-19 appear to have infected others who were more than six feet away. “These transmissions occurred inside closed spaces with insufficient ventilation. Sometimes the affected person was breathing with difficulty, for example while singing or exercising.”
The webpage says: “Under these circumstances, scientists believe that the amount of droplets and smaller infectious particles produced by people with COVID-19 became concentrated enough to spread the virus to other people. The infected people were in the same place during the same time or shortly after leaving The person infected with COVID-19. “
In a statement released immediately after the webpage was updated, the agency said it “still believes, based on current science, that people are more likely to contract infection the closer they are to a person with COVID-19.”
The CDC added: “Today’s update acknowledges that there have been some published reports that show limited and uncommon conditions where people with COVID-19 have infected others who were more than 6 feet away or shortly after the person with COVID-19 has left the area. ” The agency said the transmission occurred in “closed, poorly ventilated spaces and often involve activities that increase breathing, such as singing or exercising. Such environments and activities may contribute to the accumulation of virus-carrying particles.”
People can protect themselves by staying at least six feet from others, wearing a mask that covers their nose and mouth, washing their hands frequently, cleaning surfaces that are touched a lot, and staying home when sick. People should also avoid crowded indoor spaces and make sure indoor spaces are properly ventilated by getting outside air in as much as possible, the agency said.
Although many experts have already pointed to mounting evidence that transmission through the air plays a role in the spread of the virus, the official recognition from the CDC is sure to add to public health concerns about the risks of infection from crowded indoor spaces. Poor ventilation.
Both the presidential campaigns and the presidential debates committee say they plan to move forward with personal events less than a week after President Trump tested the new coronavirus. With more White House employees announcing that they have tested positive for the coronavirus, it is not clear what protocols have been put in place to reduce the risk of employee infection, many of whom do not wear masks and work in cramped conditions.
According to experts, when there is adequate ventilation, respiratory droplets are diluted by the outside air or pushed out by air exchange. To improve indoor airflow in public buildings, experts at the Yale School of Public Health recommend turning off sensor-based ventilation to keep the air flowing continuously. Open windows to get a refreshing breeze. The reversing ceiling fan blades can draw air away from occupants of a room.
Experts pointed to the spread of the virus in choirs, buses, fitness classes and other poorly ventilated places. In July, more than 200 aerosol biologists and other experts sent a letter expressing their concerns about airborne transmission to the World Health Organization, which responded by acknowledging “emerging evidence” that the pathogen could be spread through the air.
In a letter published Monday in the journal Science, a group of infectious disease doctors and aerosol experts confirmed more forcefully the airborne potential of the virus than the CDC did in updating it.
“The balance of attention must be shifted to protecting against transmission through the air,” they said, because people are “much more likely” to inhale a floating virus compared to being sprayed with rapidly droplets of contaminated body fluids.
The author of the letter, Kimberly Prather, an atmospheric chemist at the University of California, San Diego, said in an interview that aerosols and atmospheric transport “are the only way to explain the super-diffusion events that we see”. Once the airborne pathway is recognized, she said, this becomes a “fixable” problem with proper ventilation.
“Wear masks at all times indoors when others are present,” Brother said. Separation is important – but on the inside, there is no such thing as a completely “safe social distance”.
Some of the apparent controversy about airborne transmission may not stem from the substance but the terminology is used differently in the fields of aerosol chemistry versus infectious disease. The scientific thesis explains that fluid points up to 100 microns wide (the thickness of a sheet) can behave like an aerosol, in contrast to some definitions that focus on smaller particles.
“Aerosol biologists speak a slightly different language than doctors like me, as we look more at the practical application of transmission in order to control infection, particularly in a healthcare setting,” says Jay Butler, deputy director of the Center for Infectious Disease Control at the CDC. Diseases, he said last month. He summed up the National Academies of Sciences workshop, held in late August to discuss the mounting evidence of transmission by air, as “much more agreement than disagreement” about its possibility.
There have been several well-documented cases of the coronavirus spreading rapidly and widely in a closed or closed environment – a restaurant in Guangzhou, China; A traveling bus in the Chinese province of Zhejiang; Call center in Seoul; The Church Choir in Washington State. In this case, the singer spread the virus 45 feet away and infected more than 50 people.
Officials said these reports prompted the CDC to update its information on how the Coronavirus is transmitted. Adding to this urgency is the arrival of autumn and the cold weather, when “we were more concerned about the indoor environment,” said a scientist at the CDC who spoke on condition of anonymity because he is not authorized to speak officially.