Over 230 experts are urging the World Health Organization (WHO) to revisit their information on whether Covid-19 can be spread through airborne transmission that can lurk in indoor spaces, suggesting their hesitancy to do so is putting people in danger.
The 239 signatories from 32 countries argue the UN’s health authority needs to seriously explore the possibility that the disease can also be spread via microscopic particles pumped out by breathing and talking that can linger in indoor spaces, according to a statement by the Queensland University of Technology ahead of publication in the journal Clinical Infectious Diseases.
The WHO currently advises Covid-19 “spreads primarily through droplets of saliva or discharge from the nose when an infected person coughs or sneezes.” However, the international group of scientists says this downplays the risk, and the WHO is dragging its feet when it comes to revising its information.
“WHO’s credibility is being undermined through a steady drip-drip of confusing messages, including asymptomatic spread, the use of masks, and now airborne transmission,” Lawrence Gostin, a professor of global health law at Georgetown University who provides technical assistance to the WHO, told the Washington Post.
Critically, the debate about airborne transmission underpins many of the world’s public health strategies. For example, if the novel coronavirus truly is viable in its aerosolized airborne form, it would mean that poorly ventilated spaces — including workplace environments, schools, restaurants, buses, trains, etc — could still be potentially dangerous, even if people stick to a 2-meter social distancing rule.
“Studies by the signatories and other scientists have demonstrated beyond any reasonable doubt that viruses are exhaled in microdroplets small enough to remain aloft in the air and pose a risk of exposure beyond 1 to 2 meters by an infected person,” Professor Lidia Morawska, director of the International Air Quality and Health Laboratory, said in a statement.
Naturally, the WHO’s information on the ongoing pandemic has been subject to change when new insights have come to light about the Covid-19. The nature of airborne transmission, however, has remained the subject of long, hot debate between scientists. Some argue Covid-19 is mainly spread by larger droplets of mucus flung out by coughs, spitting, and spluttering. Since these droplets are heavy, they can only remain airborne for a short period before heading towards the ground and there’s a relatively low risk of the virus lingering in the air. On the other side of the debate, some argue that there is strong evidence the virus can spread through smaller aerosolized particles. Aerosols, or droplets smaller than 5 microns, can “float” in the air for notably longer and increases the risk of airborne transmission, especially in a stuffy room.
While the SARS-CoV-2 virus can live in the air under lab conditions for several hours, some scientists have remained doubtful of whether it can remain viable and infectious in this form. However, a number of case studies have shown the contrary. One report suggested — though it did not definitively prove — that air conditioning may have helped to infect at least nine people with Covid-19 at a restaurant in the Chinese city of Guangzhou.
Nevertheless, the debate is ongoing and, in spite of some evidence, the WHO is sticking to its guns for the meantime.
“Especially in the last couple of months, we have been stating several times that we consider airborne transmission as possible but certainly not supported by solid or even clear evidence,” Dr Benedetta Allegranzi, the WHO’s technical lead of infection prevention and control, was quoted by the New York Times.