Why admitting Covid is Airborne is so hard. - by Jeremy Chrysler - The Air Letter

No one likes to admit they were wrong and change their mind because of, well, because of evidence.

So it was when England's leading anesthetist, John Snow, set out to find the source of the cholera epidemic sweeping through London in 1854.  Foul air - miasma - was the theory of disease to which the entire medical establishment was committed.

But Snow, anesthetist to Queen Elizabeth, didn't think that made sense as a source of cholera.  So he tracked the disease - the loci of outbreaks- and identified it as originating in the water of the Broad Street pump - which turned out to be fecally contaminated due to a crack in a concrete retaining wall.

But why was that the cause of the disease?  Snow's tracking is compellingly told in the book.

But despite the success of Snow physicians remained wedded to the miasma theory - and Snow lacked another theory.  Robert Koch found it thirty years later when he identified the tubercle bacillus as the principal source of tuberculosis.  The germ theory flourished.  Bad air was disparaged as an explanation for disease transmission.  The germ theory reigns. 

But it turns out that there is a bias against aerosol transmission which is the heritage of the 19th century debates. 

This sort of prejudice led to resisting the theory that silicosis was caused by granite cutting dust rather than the germ - the tubercle bacillus.  But it turned out that it was that deadly dust - a story brilliantly told by historian Gerald Markowitz and his collaborator David Rosner.  I retell that story in my 2017 Rutgers Law Review paper Deadly Dust - a title I cribbed from Markowitz and Rosner whose subtitle is Silicosis and the Politics of Occupational Disease.

So it turns out that today's scientists have been slow to recognize aerosol transmission of Covid 19.  Jeremy Chrysler tells the tale. -  GWC

Why admitting Covid is Airborne is so hard. - by Jeremy Chrysler - The Air Letter

Evidence for airborne spread of Covid-19 is strong, but authorities underemphasize airborne protections. The curious history of infectious disease reveals how this anti-airborne bias emerged.

Jeremy Chrysler Jun 27 1

The evidence is strong that Covid spreads through the air, but neither the CDC nor the WHO will explicitly say so.

The evidence that Covid-19 spreads through the air has been there since early in the pandemic - in a Seattle choir, a Chinese restaurant, an Arkansas prison. And “Covid is Airborne” scientists have from around the globe who specialize in airborne contaminants have been pleading with authorities to tell the world, holding symposiums and writing editorial after editorial.

Phases involved in airborne transmission of respiratory viruses.

Virus-laden aerosols (<100 I1/4m) are first generated by an infected individual through expiratory activities, through which they are exhaled and transported in the environment. They may be inhaled by a potential host to initiate a new infection, provided that they remain infectious. In contrast to droplets (>100 I1/4m), aerosols can linger in air for hours and travel beyond 1 to 2 m from the infected individual who exhales them, causing new infections at both short and long ranges. CREDIT: N. CARY/SCIENCE

These aerosol experts have published studies on mask efficacy, how droplets of various sizes behave, and how air cleaners could trap the respiratory aerosols . They wrote an open letter in June of 2020 signed by hundreds of fellow scientists appealing to “national and international bodies to recognize the potential for airborne spread” of COVID-19. They have shown that 85% of viral load is in the air. They have explicitly laid out how respiratory viruses hitchhike on aerosols to penetrate the lungs and infect people.

And yet despite all this, and even as the Delta wave - as contagious as (the known-to-be-airborne) chickenpox - rages, there has been no clear guidance from the most prominent public health authorities that Covid is indeed airborne, in plain language that regular people and businesses can use to modify their own behavior and prevent airborne transmission.

Why can’t they just say “Covid is Airborne?”

The basic answer is simple: the reason authorities aren’t saying that Covid is Airborne is there is a strong bias against believing it to be true. That is, the public health and epidemiological literature almost uniformly says that airborne transmission is rare, so it’s very hard to believe that it’s actually happening at scale.

KEEP READING - the good stuff is coming