Full Version: Origins of the 5-micron aerosol confusion
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I haven't read the Apr. 28 source report yet, but there is an interesting article about the search for, and the finding of, the origins of the thought that COVID (and similar diseases) spread as droplets that fell within 6', meaning 3-6' social distancing and hand washing was the way to stop it.

The 60-Year-Old Scientific Screwup That Helped Covid Kill

Basically, someone at the CDC confounded different processes (5-micron infectious particles for TB vs influenza-like illness infections), and set 5 microns as the size of "aerosols", ignoring the range of particle sizes that stay aloft for long periods.  Once it became established, it became dogma, and anyone questioning it was dismissed.

This article reminded me of the discussion we had on the Cardboard about the 5-micron vs other sized droplets back in August, and included the 5-micron TB result, based on a UCSF Grand Rounds presentation by Don Milton (Univ of MD School of Public Health).  This was after the June discovery of where the 5-micron confusion had come from and the July letter to WHO about aerosols.

I hate to say it, but I've seen the same sort of all-in support of current CDC or WHO guidelines by many, whether it was the early CDC mask policy (not needed), the intermediate mask policy (N95 not needed unless you were a HCP), or the recently-modified policy (if fully vaccinated, masks aren't needed except rare circumstances).  I heard Stanford's Dr. Maldonado on a town-hall phone call today spinning about how exceedingly few with J&J vaccinations get COVID, without acknowledging that this "exceedingly few" is about 1/3 the rate of unvaccinated people getting COVID.   She also, I think incorrectly, hypothesized that maybe those with vaccines would mostly wind up with asymptomatic infections.  (Only 11% total asymptomatic infections among (mRNA) vaccinated and unvaccinated HCP in this study.)