Mask tests, worst-case short-distance pure-aerosol:
- increased distance somewhat protective
- cotton and surgical masks somewhat protective if worn by spreader, limited if recipient
- N95 masks highly protective on spreader, moderately highly on recipient; fit also matters
- increased distance somewhat protective
- cotton and surgical masks somewhat protective if worn by spreader, limited if recipient
- N95 masks highly protective on spreader, moderately highly on recipient; fit also matters
https://twitter.com/Reuters/status/1319232557247090688
Important:
- this is a worst-case test
- none of the masks fully protected
- hospital staff should use PAPR/CAPR if possible
- limit proximity/duration of contact
- if you think you may be infected, avoid others; wear good quality mask otherwise
msphere.asm.org/content/msph/5…
- this is a worst-case test
- none of the masks fully protected
- hospital staff should use PAPR/CAPR if possible
- limit proximity/duration of contact
- if you think you may be infected, avoid others; wear good quality mask otherwise
msphere.asm.org/content/msph/5…
Real-world viral load in respiratory secretions is likely a couple orders of magnitude lower than the viral concentrations in the aerosols used in this test:
https://twitter.com/__ice9/status/1288837252303466497?s=19
Discussion of inoculum size on probability of symptomatic infection and severity of disease:
Lower inoculum makes asymptomatic or mild cases more likely.
https://twitter.com/__ice9/status/1307082344046776321?s=19
Lower inoculum makes asymptomatic or mild cases more likely.
Accordingly, real-world efficacy studies show much better (but not 100% / RR 0.00) efficacy for N95 (~0.03) or surgical (~0.2) masks in blocking transmission.
This is roughly what we should expect from the results above. Evidence is consistent.
https://twitter.com/__ice9/status/1285621039276470273?s=19
This is roughly what we should expect from the results above. Evidence is consistent.
Earlier thread on similar mask and respirator efficacy studies with artificial viral aerosols:
Each model performed approximately as rated.
P100 full-face respirators are markedly better than N95 masks, can substitute adequately for PAPR/CAPR if needed.
https://twitter.com/__ice9/status/1241614142055821313?s=19
Each model performed approximately as rated.
P100 full-face respirators are markedly better than N95 masks, can substitute adequately for PAPR/CAPR if needed.
Building/space ventilation also further reduces transmission risk:
The experiment described in the OP above was in a closed glass tank for safety.
For pressure equilibrium reasons, this likely exaggerated the importance of mask fit.
https://twitter.com/__ice9/status/1319247855287238658?s=19
The experiment described in the OP above was in a closed glass tank for safety.
For pressure equilibrium reasons, this likely exaggerated the importance of mask fit.
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