When an infected individual coughs, sneezes, or talks, aerosols containing the virus are released into the air from their nose or mouth. These aerosols can be breathed in by anyone within 6 feet of the infected person, potentially leading to infection. However, Dale Fisher, an infectious disease physician at the National University Hospital Singapore and chair of the WHO Global Outbreak Alert and Response Network, does not believe that confusion over whether the virus is transmitted through the air has had a major impact on the pandemic. Other researchers have defended the agency's response, given the rapidly changing situation.
It is often difficult to find common ground between infection control experts and air quality physicists. People end up “talking beyond each other” due to differences in terminology. Infection control experts have traditionally drawn a hard line between droplet and airborne viruses, only considering the latter to be able to travel far and stay in the air. Marcel Loomans, an indoor air quality physicist at the Eindhoven University of Technology in the Netherlands, was disappointed but not surprised by WHO's lack of action to address the air threat after an April 1 meeting.
The disconnect between disciplines has made it difficult to analyze the big picture that is emerging. One example is the propensity of the virus to be transmitted in “superpropagation events”, where numerous individuals become infected in a single meeting by a single person. While WHO has received criticism for its response to SARS-CoV-2, some researchers are not surprised by their actions. The agency believes its role is to certify current consensus rather than promote new knowledge.
WHO has been attacked for its slow pace in recommending masks and other protective measures. Tom Frieden, president of Resolve to Save Lives and former director of the U. S. Centers for Disease Control and Prevention (CDC), understands why they may be risk-averse.
May Chu, a virologist at the Colorado School of Public Health in Aurora and member of the IPC GDG, says WHO tends to be quite conservative in its recommendations to avoid publishing incorrect information. In previous situations such as during the Ebola outbreak in West Africa and polio vaccination campaigns, WHO was more agile than during the COVID-19 pandemic. Peter Sandman, an independent risk communication specialist based in New Jersey who has worked as a consultant to WHO, believes that from the beginning WHO and other public health authorities should have emphasized that SARS-CoV-2 was a new coronavirus and that guidelines would inevitably change. Applying a preventive approach to how SARS-CoV-2 is transmitted would mean initially assuming all routes of transmission are possible.
This would require major changes in hospitals such as using negative air pressure isolation rooms and N95 masks for all staff and visitors. However, this must be weighed against evidence that they are required. Heidi Tworek, historian and public policy specialist at the University of British Columbia in Vancouver, believes part of the problem was how emphatic WHO was at the beginning of the pandemic. Attitudes have changed at WHO since then, according to Mark Sobsey from UNC Chapel Hill.