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Let’s address @AlexBerenson’s oft-repeated claim that mask-wearing does not slow the spread of respiratory viruses.
Alex calls mask requirements “a form of pseudoscientific virtue signaling and shaming”.
His proof? A single meta-analysis that does not support his statement. 1/
Alex calls mask requirements “a form of pseudoscientific virtue signaling and shaming”.
His proof? A single meta-analysis that does not support his statement. 1/
Alex cites this single meta-analysis of handwashing and masks in influenza and says “IT FINDS THEM USELESS”.
But that’s not what the Xiao, et al. study says. At all. What the Xiao analysis states is that the non-mechanical RCT studies of handwashing and masks are underpowered. https://twitter.com/alexberenson/status/1260049344696332288
But that’s not what the Xiao, et al. study says. At all. What the Xiao analysis states is that the non-mechanical RCT studies of handwashing and masks are underpowered. https://twitter.com/alexberenson/status/1260049344696332288
The Xiao meta-analysis includes some studies showing significant mask efficacy and some that don’t. They do a panel analysis.
“Some studies reported being underpowered because of limited sample size, and low adherence to hand hygiene interventions was observed in some studies.”
“Some studies reported being underpowered because of limited sample size, and low adherence to hand hygiene interventions was observed in some studies.”
High-powered RCT’s of NPI’s (non-pharmaceutical interventions) on real-world influenza spread are not easy to design and carry out.
It’s actually REALLY difficult to design a study showing whether respiratory etiquette (covering your mouth when you cough or sneeze) is effective.
It’s actually REALLY difficult to design a study showing whether respiratory etiquette (covering your mouth when you cough or sneeze) is effective.
A real-world randomly-controlled trial on NPI‘s for influenza runs into several confounds:
- Compliance with the NPI
- Recent vaccination
- Previous vaccination
- Age
- Gender
- Baseline health
- Timing of the flu season relative to study window
- Severity of the flu season
- Compliance with the NPI
- Recent vaccination
- Previous vaccination
- Age
- Gender
- Baseline health
- Timing of the flu season relative to study window
- Severity of the flu season
Despite the challenges, @UNCpublichealth’s Allison Aello found significant reductions in ILI during weeks 4–6 
& 
vs control: -35%!
“Mask use, hand hygiene & seasonal influenza-like illness among young adults: A randomized trial”, J Infect Dis. 2010. https://pubmed.ncbi.nlm.nih.gov/20088690/
& vs control: -35%!“Mask use, hand hygiene & seasonal influenza-like illness among young adults: A randomized trial”, J Infect Dis. 2010. https://pubmed.ncbi.nlm.nih.gov/20088690/
What’s odd is that the Aello et al. study is included in the Xiao meta-analysis that @AlexBerenson (wrongly) cites.
Alex seems to engage in motivated reasoning: cherry-pick a study, barely skim it without understanding its methodology & limitations, then mis-quote its conclusion
Alex seems to engage in motivated reasoning: cherry-pick a study, barely skim it without understanding its methodology & limitations, then mis-quote its conclusion
Recent studies show that wearing a surgical mask significantly reduces the amount of coronavirus-infected droplets AND aerosols coming from the wearer’s mouth.
Anyone standing near possibly-infected people (a nurse, a cashier, a security guard) should want them wearing a mask.
Anyone standing near possibly-infected people (a nurse, a cashier, a security guard) should want them wearing a mask.
The same study also showed significant reduction in emission of virus-laden droplets and aerosols when an influenza-infected person wore a surgical mask.
Leung, N.H.L., et al. Respiratory virus shedding in exhaled breath and efficacy of face masks. Nat Med 26, 676–680 (2020).
Leung, N.H.L., et al. Respiratory virus shedding in exhaled breath and efficacy of face masks. Nat Med 26, 676–680 (2020).
Again, @AlexBerenson’s repeated claims that masks don’t work to slow SARS-CoV2 spread is, to use a scientific term, bullshit.
Studies show that wearing surgical masks significantly reduces infected droplet and aerosol from the wearer’s mouth.
VERY important for face-to-face.
Studies show that wearing surgical masks significantly reduces infected droplet and aerosol from the wearer’s mouth.
VERY important for face-to-face.
Universal mask-wearing outdoors is a separate issue.
Someone jogging on the beach without a mask, maintaining social distancing, is not a significant source of viral transmission.
But the moment beachgoers line up at the lemonade stand without masks, the cashiers are at risk.
Someone jogging on the beach without a mask, maintaining social distancing, is not a significant source of viral transmission.
But the moment beachgoers line up at the lemonade stand without masks, the cashiers are at risk.
In typical Alex Berenson fashion, he does not address any of the specific critiques.
Instead, Alex does a drive-by quote-tweet to sic his trolls on a critic. Then he disappears while thousands of anonymous accounts come in with "You're a cuck" replies. https://twitter.com/AlexBerenson/status/1265395050122555392?s=20
Instead, Alex does a drive-by quote-tweet to sic his trolls on a critic. Then he disappears while thousands of anonymous accounts come in with "You're a cuck" replies. https://twitter.com/AlexBerenson/status/1265395050122555392?s=20
Different viruses shed in different ways. For example, measles morbillivirus can shed in dry skin cells, like a fine dust. It's a NIGHTMARE. Measles has an R₀ of 18!
Coronaviruses shed in droplets, not dry virions. The mask blocks most of the droplets. https://twitter.com/nuttinbuttruths/status/1265400301994913792?s=20
Coronaviruses shed in droplets, not dry virions. The mask blocks most of the droplets. https://twitter.com/nuttinbuttruths/status/1265400301994913792?s=20
I really need y'all to understand this, because you keep playing yourself. I don't have a "mask business".
We have a group of volunteers who collect masks from folks and we GIVE THEM AWAY to doctors, nurses, EMTs, police, homeless shelters, nursing homes. https://twitter.com/thexptravellers/status/1265419999604117506?s=20
We have a group of volunteers who collect masks from folks and we GIVE THEM AWAY to doctors, nurses, EMTs, police, homeless shelters, nursing homes. https://twitter.com/thexptravellers/status/1265419999604117506?s=20
This is a great question. Aerosols have some non-obvious behaviors wrt distance & particle size.
Lindsley, WG et al. (2014) studied the efficacy of face shields ALONE w/ aerosols. Note the 46cm distance vs. 183cm. distance for large vs. small particles. https://twitter.com/DanThomas12345/status/1265399764562128897?s=20
Lindsley, WG et al. (2014) studied the efficacy of face shields ALONE w/ aerosols. Note the 46cm distance vs. 183cm. distance for large vs. small particles. https://twitter.com/DanThomas12345/status/1265399764562128897?s=20
