@WHO @katierandall @linseymarr @MeganMolteni 7/ In this context, what does the new @WHO report say? - Acknowledges that infectious respiratory particles (IRPs) can be exhaled while breathing, talking etc. NOT just coughing and sneezing. GOOD!
@WHO @katierandall @linseymarr @MeganMolteni 8/ Describes transmission by the PHYSICAL mechanism by which the particles reach the susceptible person. GOOD! [This was first proposed in a paper by Prof. Yuguo Li during the pandemic] - Direct deposition of particles by ballistic trajectory (part of the old "droplets"). GOOD
@WHO @katierandall @linseymarr @MeganMolteni 9/ Airborne transmission / inhalation: when we breathe infections particles in, of any size and at any distance. Including in close proximity. GOOD - In particular this removes the old (from 1910, see history thread) repeated error that transmission in close proximity = droplets
@WHO @katierandall @linseymarr @MeganMolteni 10/ Both the direct deposition (old "ballistic droplets") and the airborne transmission / inhalation are grouped as "through the air transmission" This is awkward but not that important, in principle.
11? @carlzimmer has written a short article in @nytimes explaining all this, with some more links of interest: nytimes.com/2024/04/18/hea…
@carlzimmer @nytimes 12/ A pearl on that article: a medical expert complaining that the old terminology was nice because it was simple to apply EVEN IF IT WAS WRONG [Even it people in hospitals got sick and died because of the wrong protections -- OMG!] Not that uncommon... nytimes.com/2024/04/18/hea…
@carlzimmer @nytimes 13/ So overall, while not perfect, and with that awkwardness that can often arise of a "written by a large committee with strong internal disagreements", I view this as progress @WHO still has not apologized for their huge errors. I hope they do one day. But this is progress
@carlzimmer @nytimes @WHO 14/ Now, the more important decision is WHAT DO WE DO WITH THIS? WHEN should we use protections for airborne inhalation, such as N95/FFP2 respirators, enhanced ventilation / filtration, CO2 meters etc? The @WHO report explicitly says that they do NOT take a position on that
@carlzimmer @nytimes @WHO 15/ Conceptually, we need a needle at a point between 2 extremes: - A (theoretical) mild disease w/ minor airborne component. Airborne protections may not be worth the costs - (theoretical) extremely deadly disease w/ major airborne component: definitely airborne protections
@carlzimmer @nytimes @WHO 16/ The key question, that this report doesn't take a position on, is: When is a disease serious enough to recommend airborne protections? @WHO doesn't want to recommend N95s if poor countries don't have them. Fears health care workers there would refuse to work w/o them
@jljcolorado @carlzimmer @nytimes @WHO Thanks for the summary, Jose. In the last couple of days, I have been wondering about settings like extremely packed suburban trains and buses, very very crowded housing, etc in places like India. What is your sense of airborne vs deposition vs contact in those types of settings?
@PrasadKasibhat1 @jljcolorado @carlzimmer @nytimes @WHO Don't know if this helps x.com/john_p_topham/…
@PrasadKasibhat1 @jljcolorado @carlzimmer @nytimes @WHO Don't know if this helps x.com/john_p_topham/…