When Did Respiratory Diseases Become Non-Respiratory?

In the important first 12 months of the COVID-19 pandemic, we believe that the two major healthcare mistakes made by the CDC and WHO were:

1. Spreading disinformation about the non-respiratory spread of COVID-19 (this post).

2. Not prioritizing individual risk levels for who is at greatest risk for severe disease (next post).

In March 2020, I was criticized by friends who work in medicine for wearing a mask in the car while bringing my college student home from the airport. I am still shocked that:

  1. The White House Chief Medical Advisor stressed that COVID-19 was primarily spread by non-airborne transmission up until September 2020, when the CDC finally DID state the importance of airborne transmission – only to remove the statement. Finally, on May 7, 2021 (~18 months since the COVID-19 Pandemic began), the CDC acknowledged that aerosol inhalation is important for transmission.

  2. In March 2020, The WHO also emphatically stated that COVID-19 was not spread by airborne transmission. It took until March, 2022 for the WHO to correct their guidance.

  3. Many of our colleagues who work in medicine put aside their medical training and believed that COVID-19 was primarily non-airborne transmitted. Of course, I dismissed the fallacy that COVID-19 was primarily spread via droplets that people then somehow touched and put on their face. Of course it was airborne (aerosols). That is how respiratory diseases tend to spread.

A fascinating review article by Jimenez, et al. published in August 2022 by the Intern J Indoor Environ Health, details the historical thinking of airborne diseases. Hippocrates understood airborne diseases in 400 BC, but the WHO could not understand this until 2022. The main reason is the misconception that a respiratory drop could not stay airborne if it was greater than 5 microns. In the 1960’s, doctors insisted that the only disease that was transmitted by airborne particles was tuberculosis.

A respiratory particle the size of 5 microns has been the cut point for airborne diseases, although it was never validated. It was always just considered the “gold standard” by which a disease could be transmitted by air – or not. The confusion is complicated by the following variables that compound a static cut point of 5 microns (whether it can travel by air or not):

  • Aerosols smaller than 5 microns can linger in the air

  • Aerosols can accumulate in poorly ventilated spaces

  • Aerosols can be inhaled at both long and short-ranges

  • Particles as large as 100 microns can remain suspended in air for >5 seconds and can travel beyond 1 meter

  • The number and viral load of aerosols produced from speaking and other expiratory activities are typically much HIGHER than from droplets

The conundrum involves determining if a disease is primarily spread by airborne or respiratory droplets. One could blame decisions made by the CDC & WHO on the dearth of studies in the last two decades about the impact of airborne vs. droplet transmitted diseases. However, the Fitzpatrick team questions this argument. COVID-19 is a common cold coronavirus similar to SARS. SARS was recognized by the WHO as an airborne virus. In fact, an August 2021 SCRIPPS article stated that SARS, MERS, influenza, measles and rhinoviruses all spread via aerosols that can build up indoors and linger in the air for hours.

It’s also about viral load. Back in May 2020, the Fitzpatrick team posted the importance of viral load and immunity (or no immunity). Although Omicron strains have become increasingly easier to contract, this refers to how much of the infection a person needs for it to become infectious. As we posted, when someone sneezes, up to 20 million particles can be released. How many particles will fall to the ground and how many will stay suspended in the air? That is the question that needs to be answered.

WHY it matters: Health Policy Decisions. 

  • In May 2020, I attended a local city council meeting. All of the tables were being vigorously scrubbed down with alcohol, yet no one (except myself) wore a mask. Lysol wipes and alcohol were in extremely high demand (always out of stock), as we were continuously lectured that this was HOW TO PREVENT COVID-19. The risk of airborne transmission from sneezes, etc. absolutely dwarfs the risk of transmission from touching contaminated surfaces.

  • Misplaced dollars were spent creating plexiglass barriers in countless schools and offices. This was usually a bad idea because it prevented ventilation/airflow and allowed large build-ups of contaminants in confined spaces.

  • Faster acceptance of airborne transmission should have made more LOGICAL guidelines that distinguished outdoor events vs. indoor events.

Our Recent Posts:
COVID-19 Round 2: Reinfection
The Unseasonal Cold and Flu (Season)

Kevin Fitzpatrick, President at Fitzpatrick Translational Science, Inc.
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