239 Experts With 1 Big Claim: The Coronavirus Is Airborne

But interviews with nearly 20 scientists — including a dozen W. H.O. 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 W. H.O.’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 W.H.O. 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 longstanding W. H.O. 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.

“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.”