(2021-05-07) Opinion Why Did It Take So Long To Accept The Facts About Covid

Zeynep Tufekci - Opinion | Why Did It Take So Long to Accept the Facts About Covid-19? A week ago, more than a year after the World Health Organization (WHO) declared that we face a pandemic, a page on its website titled “Coronavirus Disease (Covid-19): How Is It Transmitted?” got a seemingly small update.

The revised response still emphasizes transmission in close contact but now says it may be via aerosols — smaller respiratory particles that can float — as well as droplets. It also adds a reason the virus can also be transmitted “in poorly ventilated and/or crowded indoor settings,” saying this is because “aerosols remain suspended in the air or travel farther than 1 meter.

If the importance of aerosol transmission had been accepted early, we would have been told from the beginning that it was much safer outdoors, where these small particles disperse more easily, as long as you avoid close, prolonged contact with others. We would have tried to make sure indoor spaces were well ventilated, with air filtered as necessary. Instead of blanket rules on gatherings, we would have targeted conditions that can produce superspreading events: people in poorly ventilated indoor spaces, especially if engaged over time in activities that increase aerosol production, like shouting and singing. We would have started using masks more quickly, and we would have paid more attention to their fit, too. And we would have been less obsessed with cleaning surfaces.

Since the pandemic is far from over, with countries like India facing devastating surges, we need to understand both why this took so long to come about and what it will mean.

*The implications of this were illustrated when I visited New York City in late April — my first trip there in more than a year.

A giant digital billboard greeted me at Times Square, with the message “Protecting yourself and others from Covid-19. Guidance from the World Health Organization.”*

That billboard neglected the clearest epidemiological pattern of this pandemic: The vast majority of transmission has been indoors, sometimes beyond a range of three or even six feet. The superspreading events that play a major role in driving the pandemic occur overwhelmingly, if not exclusively, indoors. The billboard had not a word about ventilation, nothing about opening windows or moving activities outdoors, where transmission has been rare and usually only during prolonged and close contact

This assumption that these larger droplets that can travel only a few feet are the main way the disease spreads is one of the key reasons the W.H.O. and the C.D.C. didn’t recommend masks at first. Why bother if one can simply stay out of their range? After the C.D.C. recommended masks in April 2020, the W.H.O. shifted last June, but it first suggested ordinary people generally wear masks if physical distancing could not be maintained, and still said health care workers performing screenings in the community did not need to wear masks if they could stay that single meter away from patients. The W.H.O. last updated its mask guidance in December but continued to insist that mask use indoors was not necessary if people could remain separated by that mere meter

In contrast, if the aerosols had been considered a major form of transmission, in addition to distancing and masks, advice would have centered on ventilation and airflow, as well as time spent indoors. Small particles can accumulate in enclosed spaces, since they can remain suspended in the air and travel along air currents

the C.D.C. did not really accept aerosol transmission until October, though still relegating it to a secondary role until its change on Friday, which put the risk infection from inhaling these tiny particles first on its list of means of transmission.

Along the way to modern public health shaped largely by the fight over germs, a theory of transmission promoted by the influential public health figure Charles Chapin took hold. Dr. Chapin asserted in the early 1900s that respiratory diseases were most likely spread at close range by people touching bodily fluids or ejecting respiratory droplets, and did not allow for the possibility that such close-range infection could occur by inhaling small floating particles others emitted. He was also concerned that belief in airborne transmission, which he associated with miasma theories, would make people feel helpless and drop their guard against contact transmission. This was a mistake that would haunt infection control for the next century and more.

in early 2020 that the W.H.O. and the C.D.C. asserted that SARS-CoV-2 was transmitted primarily via these heavier, short-range droplets,

But from the beginning, the way the disease was spreading around the world did not fit this theory well. In February 2020, after an infected person was found to have boarded the cruise ship.

Hitoshi Oshitani, a Japanese virologist who played an important role in his country’s response to the epidemic, said it was this ship outbreak that helped convince him this was airborne — and it’s why Japan planned around airborne transmission assumptions from as early as February 2020.

Then there were the many superspreader events around the world that defied droplet explanations

Finally, it was clear from early on that people who weren’t yet sick or coughing or sneezing — which produce a lot more droplets — were transmitting and that things correlated with aerosol emissions like talking, yelling and singing were associated with many of the outbreaks.

Linsey Marr, a professor of engineering at Virginia Tech who made important contributions to our understanding of airborne virus transmission before the pandemic, pointed to two key scientific errors — rooted in a lot of history — that explain the resistance, and also opened a fascinating sociological window into how science can get it wrong and why

Why did it take so long to understand all this?

One reason is that our institutions weren’t necessarily set up to deal with what we faced. For example, the W.H.O.’s Infection Prevention and Control (I.P.C.) global unit primarily concentrates on health care facilities.

Another dynamic we’ve seen is something that is not unheard-of in the history of science: setting a higher standard of proof for theories that challenge conventional wisdom than for those that support it.

The skepticism about airborne transmission is at odds with the acceptance of droplet transmission. Dr. Marr and Joseph Allen, the director of the Healthy Buildings program and an associate professor at Harvard’s T.H. Chan School of Public Health, told me that droplet transmission has never been directly demonstrated.

Righting this ship cannot be a quiet process — updating a web page here, saying the right thing there. The proclamations that we now know are wrong were so persistent and so loud for so long.

big proclamations require probably even bigger proclamations to correct, or the information void, unnecessary fears and misinformation will persist, damaging the W.H.O. now and in the future.