WHO urged to warn of airborne spread

Scientists have long contended that the coronavirus can linger in the air.

The World Health Organization on Tuesday agreed to formally acknowledge the threat aerosols play in the transmission of the virus that causes COVID19 in indoor spaces, after receiving an open letter put forward by 239 researchers in 32 countries.

WHO agency scientists said during a news briefing that they would review evidence on transmission of the virus and update its recommendations accordingly in a few days.

In an open letter published by the Oxford Academic scientific journal Monday, the group of scientists accuses the international health agency of ignoring evidence that microscopic particles are released during exhalation that remain aloft in the air and travel further than the established 6foot physically distancing guidelines set for indoor spaces such as offices, markets, restaurants, stores and other businesses.

“We appeal to the medical community and to the relevant national and international bodies to recognize the potential for airborne spread of COVID19,” the letter reads.

Until Tuesday, the WHO maintained that the virus is spread primarily by large respiratory droplets, released when an infected person coughs or sneezes, that fall to the ground; or by touching a contaminated surface and then touching your face.

“Airborne transmission is the fourth factor,” said Mark R. Cullen, founding director of the Center for Population Health Sciences at Stanford University. “There’s a big debate as how important it should be.”

In its latest coronavirus update, published June 29, the WHO dismissed the possibility of airborne transmission, except for inside health care settings. The agency asserted that hand washing and social distancing are the most effective ways to curb the spread of the virus.

Dr. Benedetta Allegranzi, who leads the WHO’s committee on infection prevention and control, on Tuesday reconsidered that conclusion, saying that aerosol spread in “crowded, closed, poorly ventilated settings, cannot be ruled out.”

The letter presented by Lidia Morawska, a professor of atmospheric sciences and environmental engineering at the Queensland University of Technology in Brisbane, Australia, said the agency urgently needs to provide clear preventive measures on airborne transmission. Specifically, it suggests the WHO promotes efficient ventilation and discourages overcrowding in public spaces.

It also calls on the WHO to recommend that people avoid overcrowding, particularly on public transportation and in other confined spaces.

“We are concerned that the lack of recognition of the risk of airborne transmission of COVID19 and the lack of clear recommendations on the control measures against the airborne virus will have significant consequences,” the scientists wrote. “People may think they are fully protected by adhering to the current recommendations but, in fact, additional airborne interventions are needed.”

The WHO has been criticized for lagging behind the scientific community in its response to the coronavirus pandemic. In two alarming instances, the agency declined to recommend maskwearing for the general public during the early stages of the pandemic and asserted that transmission of the virus by asymptomatic individuals is “very rare.” It walked back both claims following pushback from researchers.