The WHO Acknowledges That Covid-19 Can Be Airborne Indoors
Experts have criticized the organization for not doing so sooner
This week, the World Health Organization (WHO) was widely criticized by science experts for failing to acknowledge that the coronavirus could be transmitted through the air in indoor spaces.
A paper authored by 239 experts, accepted into the journal Clinical Infectious Diseases on Monday, argued that, “beyond any reasonable doubt,” the coronavirus could be spread through tiny droplets released when people breathe, talk, and cough. Crucially, it pointed out that these droplets could “remain aloft in air” and pose a risk of exposure even at distances beyond six feet. On Tuesday, the WHO said it would revisit the evidence, and the organization’s head of infection prevention and control, Benedetta Allegranzi, MD, acknowledged that the possibility of airborne transmission in “crowded, closed, poorly ventilated settings, cannot be ruled out.”
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On Thursday, the WHO formally updated its stance on airborne transmission through a new Q&A page, titled “How is Covid-19 transmitted?”
While the WHO maintains that Covid-19 is primarily spread through large droplets expelled from the nose and mouth that are breathed in when people come into close contact, it acknowledged that aerosol transmission indoors “cannot be ruled out,” echoing Allegranzi’s statement. By choosing this language, the WHO recognizes that indoor transmission is possible but avoids directly stating that it’s known to occur — a very different statement than that made by the group of 239 experts.
The WHO notes that indoor transmission could happen in crowded, inadequately ventilated spaces such as “restaurants, nightclubs, places of worship, or places of work where people may be shouting, talking, or singing.” It also emphasizes that airborne spread is a concern for health care workers, who can be exposed to aerosolized droplets created through certain medical procedures. Previously, the WHO only specified this group of people in its guidance about aerosol transmission. Now, indoor transmission is a possibility everyone must reckon with.