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Had quite a bit of backlash to our paper, published last week, which set out 10 streams of evidence supporting predominance of AIRBORNE spread of SARS-CoV-2. I respond to some criticisms in this thread.
1/ https://linkinghub.elsevier.com/retrieve/pii/S0140673621008692
1/ https://linkinghub.elsevier.com/retrieve/pii/S0140673621008692
Criticism 1: âThe paper is just opinion, and several authors arenât even doctors.â
Response: No. Itâs well-researched scholarly argument, produced by an interdisciplinary team of 6 professors including 3 docs, 2 aerosol scientists and 1 social scientist.
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Response: No. Itâs well-researched scholarly argument, produced by an interdisciplinary team of 6 professors including 3 docs, 2 aerosol scientists and 1 social scientist.
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Criticism 2: âSure, the virus may be airborne, but this is a minor issue. Droplets are so much bigger and more infectious.â
Response: We disagree. Most infection happens by INHALATION. Every gulp of infected air contains thousands of tiny viral-laden particles.
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Response: We disagree. Most infection happens by INHALATION. Every gulp of infected air contains thousands of tiny viral-laden particles.
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Criticism 3: âLaboratory studies are artificial and low-quality. Viable SARS-CoV-2 virus has never been isolated from ordinary room air.â
Response: Incorrect. People who make these claims are cherry-picking evidence and misclassifying excellent lab studies as âlow-qualityâ.
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Response: Incorrect. People who make these claims are cherry-picking evidence and misclassifying excellent lab studies as âlow-qualityâ.
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Criticism 4: âHalf air sampling studies found no virus, therefore the virus is not airborne or airborne is minor route.â
Response: Logical fallacy. If I go for a walk and donât see a kingfisher, this proves neither that kingfishers donât exist nor that theyâre almost extinct.
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Response: Logical fallacy. If I go for a walk and donât see a kingfisher, this proves neither that kingfishers donât exist nor that theyâre almost extinct.
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Criticism 5: âIn contrast to the sparse and flawed studies of aerosols, the virus has been easily and consistently cultured from droplets.â
Response: Incorrect. The only evidence cited to support this claim seems to be âunpublished data from my labâ.
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Response: Incorrect. The only evidence cited to support this claim seems to be âunpublished data from my labâ.
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Criticism 6: âThis droplet v aerosol argument is just semantics. It doesnât change the recommendations.â
Response: No itâs not just semantics. âPredominantly airborneâ means we need a RADICALLY different approach to prevention policy (next tweet).
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Response: No itâs not just semantics. âPredominantly airborneâ means we need a RADICALLY different approach to prevention policy (next tweet).
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Airborne precautions include:
Ventilation. Open windows and doors, encourage draughts.
Air filtration w HEPA filters (+ DISCOURAGE air-recycling air-conditioning).
Ensure masks are high-quality, well-fitting and worn whenever indoors.
Limit time indoors.
Avoid close contact.
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Ventilation. Open windows and doors, encourage draughts.
Air filtration w HEPA filters (+ DISCOURAGE air-recycling air-conditioning).
Ensure masks are high-quality, well-fitting and worn whenever indoors.
Limit time indoors.
Avoid close contact.
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Criticism 7: âAirborne infection occurs beyond 2m. The virus spreads mostly via close contact. Therefore close-contact spread isnât airborne.â
Response: Logical fallacy. MOST airborne spread occurs at CLOSE RANGE (physics innit: particles donât magically jump the first 2m).
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Response: Logical fallacy. MOST airborne spread occurs at CLOSE RANGE (physics innit: particles donât magically jump the first 2m).
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Criticism 8: âGiven that anything smaller than 5 microns is a droplet, and droplets fall within 2m, we can largely forget about transmission beyond 2m.â
Response: Incorrect. Particles of up to 100 microns travel far beyond 2m in the air, so physical distancing isnât enough.
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Response: Incorrect. Particles of up to 100 microns travel far beyond 2m in the air, so physical distancing isnât enough.
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Criticism 9: âThe paper is scaremongering. If we say SARS-CoV-2 is spread through the air, people will panic.â
Response: But it IS spread through air, and until we acknowledge that, our measures to control its spread will be ineffective. Lying isnât an effective strategy.
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Response: But it IS spread through air, and until we acknowledge that, our measures to control its spread will be ineffective. Lying isnât an effective strategy.
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Criticism 10: âOkay itâs airborne, but itâs not PREDOMINANTLY airborneâ.
Response: The evidence suggests that it is. Super-spreader events have no other explanation. Over-dispersion. Long-range infection in quarantine hotels. Many other examples in the paper. Please read it.
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Response: The evidence suggests that it is. Super-spreader events have no other explanation. Over-dispersion. Long-range infection in quarantine hotels. Many other examples in the paper. Please read it.
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Criticism 11: âA systematic review came to the opposite conclusion.â
R: A review isnât gold-standard if it a) omitted topic experts, b) asked an overly narrow question, c) misclassified high-quality studies as low-quality, d) failed to account for disconfirming evidence.
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R: A review isnât gold-standard if it a) omitted topic experts, b) asked an overly narrow question, c) misclassified high-quality studies as low-quality, d) failed to account for disconfirming evidence.
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Criticism 12: âBut systematic reviews are always more rigorous than narrative reviewsâ.
Response: No theyâre not. We scotched that flawed assumption here:
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6001568/
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Response: No theyâre not. We scotched that flawed assumption here:
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6001568/
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Criticism 13: âThe paper is an ad hominem attack against individuals in the WHO.â
Response: Please read the paper. Itâs not personal. Thousands are dying daily. Weâre begging WHO to show scientific leadership at this historical moment, in the face of overwhelming evidence.
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Response: Please read the paper. Itâs not personal. Thousands are dying daily. Weâre begging WHO to show scientific leadership at this historical moment, in the face of overwhelming evidence.
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PS some animations here, thanks to @VickiGSP https://www.phc.ox.ac.uk/research/resources/aerosols-and-making-spaces-space
