Read on Twitter
1/ TIME FOR SOME AIRBORNE + DROPLET HISTORY
Now that @WHO and @CDCgov have finally accepted *after a year of denial and delays* that airborne transmission is a major mode for COVID-19, it is time to review the history to try to understand why this response was so poor.
Now that @WHO and @CDCgov have finally accepted *after a year of denial and delays* that airborne transmission is a major mode for COVID-19, it is time to review the history to try to understand why this response was so poor.
2/ Remember, the evidence is overwhelming that airborne transmission (1 to 1 in close proximity, and 1 to many in shared room air = superspreading) is the dominant mode of transmission. https://twitter.com/jljcolorado/status/1383566908797059078
3/ And probably we are being charitable by saying only "dominant." Can't find any real evidence that airborne is not 99%. Airborne can explain all the epidemiological patterns, while large droplets and fomites can't, and they are pathetically lacking ev. https://twitter.com/jljcolorado/status/1390497149574651906
4/ @zeynep published an outstanding article yesterday in the @nytimes where she explains the context, the implications, and some of the history.
I wanted to give some more historical detail, without the word limits that she faced in @nytimes. https://www.nytimes.com/2021/05/07/opinion/coronavirus-airborne-transmission.html
I wanted to give some more historical detail, without the word limits that she faced in @nytimes. https://www.nytimes.com/2021/05/07/opinion/coronavirus-airborne-transmission.html
5/ Why does this matter? bc we still face resistance. We have seen how @WHO and others do the changes too quietly, and they don't communicate how the mitigations need to change. And in many countries they report that mssg doesn't arrive, still focusing on disinfection + plexiglas
6/ We have written an article on history. Started by trying to figure out where 5 micron error for droplet / aerosol boundary came from, since physics tells us it is ~100 um. E.g. see this video of 50 micron particles, ain't falling to the ground quickly: https://twitter.com/MicroLevitator/status/1283556047471378432
7/ But as we investigated the origins of the 5 micron error, we learned a lot more about the history of infectious disease transmission, which is the root of the resistance and delays of @WHO and @CDCGov. As we'll see, the creation of the @CDCGov is deeply embedded in the errors!
8/ Our preprint on the history can be read here. Written by @katierandall, @EThomasEwing, @linseymarr, Lydia Bourouiba and yours truly.
https://papers.ssrn.com/sol3/papers.cfm?abstract_id=3829873
https://papers.ssrn.com/sol3/papers.cfm?abstract_id=3829873
9/ We need to go back to the origins of theories about the transmission of diseases. Hippocrates ( https://en.wikipedia.org/wiki/Hippocrates) in ancient Greece proposed that diseases were transmitted through the air.
[I think doctors still do the Hippocratic Oath: https://en.wikipedia.org/wiki/Hippocratic_Oath]
[I think doctors still do the Hippocratic Oath: https://en.wikipedia.org/wiki/Hippocratic_Oath]
The Hippocratic text "On the Nature of Man" reads:
"Whenever many men are attacked by one disease at the same time, the cause should be assigned to that which is most common, and which we all use most. This it is which we breathe in." https://www.loebclassics.com/view/hippocrates_cos-nature_man/1931/pb_LCL150.25.xml
"Whenever many men are attacked by one disease at the same time, the cause should be assigned to that which is most common, and which we all use most. This it is which we breathe in." https://www.loebclassics.com/view/hippocrates_cos-nature_man/1931/pb_LCL150.25.xml
11/ Throughout much of human history, belief persisted that diseases were transported through the air. Coming from putrid matter, traveling long distances (e.g. a person infected by the flu in Boston could infect someone in UK)
This was miasma theory: https://en.wikipedia.org/wiki/Miasma_theory
This was miasma theory: https://en.wikipedia.org/wiki/Miasma_theory
12/ The idea of person-to-person transmission, which now seems obvious (e.g. we get COVID-19, the flu, or tuberculosis from another person) wasn't seriously considered till Italian physician Girolamo Fracastoro proposed it in 1546: https://en.wikipedia.org/wiki/Girolamo_Fracastoro
13/ The debate ensued for centuries between the miasmatists and the contagionists.
https://oyc.yale.edu/history/hist-234/lecture-13
https://oyc.yale.edu/history/hist-234/lecture-13
14/ A middle ground was devised, "Contingent Contagionism" https://en.wikipedia.org/wiki/Contingent_contagionism
15/ CC was "a qualified way of rejecting application of term "contagious disease" for a particular infection. E.g. it could be stated that cholera, or typhus, was not contagious in a "healthy atmosphere", but might be contagious in an "impure atmosphere" https://en.wikipedia.org/wiki/Contingent_contagionism
16/ Eerie how that applies to COVID-19. Highly contagious under some low ventilation conditions, much less so under well ventilated or outdoor conditions.
E.g. our preprint, where we reproduce indoor superspreading quantitatively with an airborne model: https://twitter.com/jljcolorado/status/1388948704384725000
E.g. our preprint, where we reproduce indoor superspreading quantitatively with an airborne model: https://twitter.com/jljcolorado/status/1388948704384725000
17/ Florence Nightingale was a contingent contagionist.
During the Crimean war in the 1850s, she greatly reduced infection rates with social distance & ventilation. https://en.wikipedia.org/wiki/Florence_Nightingale
During the Crimean war in the 1850s, she greatly reduced infection rates with social distance & ventilation. https://en.wikipedia.org/wiki/Florence_Nightingale
18/ In 1854, there is a cholera epidemic in London. The public health established believed it to be caused by a miasma (bad air).
John Snow ( https://en.wikipedia.org/wiki/John_Snow ) shows that it is transmitted through water!
John Snow ( https://en.wikipedia.org/wiki/John_Snow ) shows that it is transmitted through water!
