SAN FRANCISCO, July 06, (THEWILL) – 239 scientists in 32 countries, in an open letter to the World Health Organisation (WHO), have outlined evidence showing that smaller particles can infect people and are calling for the agency to revise its recommendations on the virus being airborne.
The WHO has long held that the coronavirus is spread primarily by large respiratory droplets that, once expelled by infected people in coughs and sneezes, fall quickly to the floor.
Even in its latest update on the coronavirus, released June 29, the WHO said airborne transmission of the virus is possible only after medical procedures that produce aerosols, or droplets smaller than 5 microns. (A micron is equal to 1 millionth of a meter.)
Proper ventilation and N95 masks are of concern only in those circumstances, according to the WHO. Instead, its infection control guidance, before and during this pandemic, has heavily promoted the importance of handwashing as a primary prevention strategy, even though there is limited evidence for transmission of the virus from surfaces. (The Centers for Disease Control and Prevention now says surfaces are likely to play only a minor role.)
But interviews with nearly 20 scientists — including a dozen WHO consultants and several members of the committee that crafted the guidance — and internal emails paint a picture of an organization that, despite good intentions, is out of step with science.
Whether carried aloft by large droplets that zoom through the air after a sneeze, or by much smaller exhaled droplets that may glide the length of a room, these experts said, the coronavirus is borne through air and can infect people when inhaled.
Most of these experts sympathized with the WHO’s growing portfolio and shrinking budget, and noted the tricky political relationships it has to manage, especially with the United States and China. They praised WHO staff for holding daily briefings and tirelessly answering questions about the pandemic.
But the infection prevention and control committee in particular, experts said, is bound by a rigid and overly medicalized view of scientific evidence, is slow and risk-averse in updating its guidance and allows a few conservative voices to shout down dissent.
“They’ll die defending their view,” said one long-standing WHO consultant, who did not wish to be identified because of her continuing work for the organization. Even its staunchest supporters said the committee should diversify its expertise and relax its criteria for proof, especially in a fast-moving outbreak.
“I do get frustrated about the issues of airflow and sizing of particles, absolutely,” said Mary-Louise McLaws, a committee member and epidemiologist at the University of New South Wales in Sydney.
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“If we started revisiting airflow, we would have to be prepared to change a lot of what we do,” she said. “I think it’s a good idea, a very good idea, but it will cause an enormous shudder through the infection control society.”
If airborne transmission is a significant factor in the pandemic, especially in crowded spaces with poor ventilation, the consequences for containment will be significant. Masks may be needed indoors, even in socially distant settings. Health care workers may need N95 masks that filter out even the smallest respiratory droplets as they care for coronavirus patients.
According to an article which originally appeared in The New York Times, Ventilation systems in schools, nursing homes, residences and businesses may need to minimize recirculating air and add powerful new filters. Ultraviolet lights may be needed to kill viral particles floating in tiny droplets indoors.
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