WHO reviewing evidence of possible airborne transmission of coronavirus

WHO reviewing evidence of possible airborne transmission of coronavirus
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The World Health Organization (WHO) said it is reviewing evidence of possible airborne transmission of the novel coronavirus after a group of more than 200 scientists called on the agency to recognize the method of transmission in an open letter.

Maria Van Kerkhove, who heads the agency’s emerging diseases and zoonosis unit, said at a media briefing on Tuesday that officials have “been talking about the possibility of airborne transmission, aerosol transmission, as one of the modes of transmission of COVID-19 as well as droplets.”

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Kerkhove added that the agency will be issuing a “brief in the coming days and that will outline everything that we have in this area.”

Nearly 240 scientists representing more than 30 countries recently called on the agency to update its recommendations for the virus based on evidence they say supports the possibility of airborne transmission.

“There is significant potential for inhalation exposure to viruses in microscopic respiratory droplets (microdroplets) at short to medium distances (up to several meters, or room scale), and we are advocating for the use of preventive measures to mitigate this route of airborne transmission,” the group wrote in the letter. 

“It is understood that there is not as yet universal acceptance of airborne transmission of SARS-CoV2 (the novel coronavirus that causes COVID-19); but in our collective assessment there is more than enough supporting evidence so that the precautionary principle should apply. In order to control the pandemic, pending the availability of a vaccine, all routes of transmission must be interrupted,” they added.

On a web page outlining modes of transmission for the novel coronavirus, the WHO states that the virus is “primarily transmitted between people through respiratory droplets and contact routes.”

Though the organization notes that airborne transmission “may be possible in specific circumstances and settings in which procedures or support treatments that generate aerosols are performed,” it also states that in an analysis of more than 70,000 COVID-19 cases in China, that particular mode of transmission was not reported.

However, the scientists' letter pointed to studies they say “have demonstrated beyond any reasonable doubt" that the virus can be released during "exhalation, talking, and coughing in microdroplets" that can remain in the air and pose a risk to those who may inhale that same air 1-2 meters from an infected person.  

The group recommends, “sufficient and effective ventilation” for people in public buildings, workplace environments, schools, hospitals and nursing homes, as well as supplementing “general ventilation with airborne infection controls such as local exhaust, high efficiency air filtration, and germicidal ultraviolet lights” to mitigate the effects of what they believe is the aerosolized disease. 

The risk, the scientists added, is of “heightened significance” now as more states and countries have continued to ease coronavirus restrictions and are moving to reopen workplaces and schools amid the ongoing pandemic.

The news comes as the United States has seen high surges of COVID-19 in states such as Texas, Florida, Arizona, Georgia and Alabama, forcing local leaders to roll back reopening efforts and declare states of emergency.

The surge has also prompted state governors like Michigan's Gretchen Whitmer (D) to call for a nationwide "mask up" campaign, asking even those in the White House to wear a face mask and exemplify proper safety behaviors.