Huge meta-study (n=172) concludes chance of transmission falls from 17.4% to 3.1% when wearing face masks:
Physical distancing was also very important. Eye protection, less so.
Chu, Derek K., Elie A. Akl, Stephanie Duda, Karla Solo, Sally Yaacoub, Holger J. Schünemann, and COVID-19 Systematic Urgent Review Group Effort (SURGE) study authors. 2020. “Physical Distancing, Face Masks, and Eye Protection to Prevent Person-to-Person Transmission of SARS-CoV-2 and COVID-19: A Systematic Review and Meta-Analysis.” The Lancet, June.
Some other interesting results from a study on the Plague Marines aboard the aircraft carrier USS Theodore Roosevelt:
Looks like washing hands more than normal made no difference.
As Lyman Stone notes, what is especially striking is that this refers to individual protection, not community based protection (mask compliance was ~75% but entirely after the infection had become widespread).
Payne, Daniel C. 2020. “SARS-CoV-2 Infections and Serologic Responses from a Sample of U.S. Navy Service Members — USS Theodore Roosevelt, April 2020.” MMWR. Morbidity and Mortality Weekly Report 69. https://doi.org/10.15585/mmwr.mm6923e4.
I know I am beating a dead horse, having already written a couple of effortposts on this topic. Nonetheless, always nice to have priors confirmed, even if most people have already made up their minds.
What is the cost to benefit ratio in buying hospital grade ppe, or a bsl3 suit?
Another Lancet Article. How long till the Retraction?
When I wrote Scientific/Medical articles of my research The Lancet was viewed as one of the poorest quality Journals in which to publish your work. Glad to see it has continued in that vein.
Please keep off topic posts to the current Open Thread.
If you are new to my work, start here.
Amazing sensation: 2×2=4. Who could have thought?
I don’t know about the Lancet (never did purely medical research), but both Science and Nature can merge into one Journal of Irreproducible Results.
Impact is the worst enemy of quality: when 40 papers next year cite you and say that the results are groundbreaking, you get an impact of 40. When 40 papers next year cite you and say that your paper is complete BS, you get an impact of 40. Case closed.
count me in when it comes for rooting for masks. However it is interesting that one of the most important Corona experts in Germany – Prof. Streeck – says in an interview published today that he is rather critical of masks.
Some stickler points:
The effect of extra hand-washing turns on the baseline level, which is high already for hygienic people and should be extra-high among sailors.
Unless they have corrected for it, we should expect serious confounding between mask wearing, physical distancing, and hermitism. That is to say, someone who wears a mask is also more likely to practice physical distancing than someone who isn’t, making it hard to tell cause from effect.
Yes, the relationship may have been found because masks appeal to more cautious people, even while they may actually discourage caution.
Some handgun manufacturers have noticed this effect as regards the safety catch. Cautious people use it better, but its existence can make everyone less cautious. They therefore don’t implement one.
Dude, that’s just Big Mask trying to gin up sales of masks!
https://www.zerohedge.com/markets/big-pharma-criminal-influence-research-exposed-secret-recording-lancet-and-nejm-editors
I visited a large hospital in Virginia where my 90 year old mother met her heart doctor for a routine appointment. We wore our symbolic masks. Most employees in the hospital had masks that were clearly ineffective. One could see the mask expand, and release expelled breath at the sides and top and bottom, as they exhaled. About 20% had no masks. The heart doctor had a mask that appeared plastered to his face. I suppose this was the real thing in his case. He was the only one. Can’t help being a little skeptical about these masks, or that they provide any meaningful protection.
Did he say why? US govt’s deadly aversion to masks stems from the fear that the public usage will take away the masks from doctors.
What is this prof’s excuse?
his point is that people don’t use them properly, the get dirty and potentially infectious and people wear them to long without cleaning.
So essentially he thinks the public is too stupid for masks. Why not broadcast the proper usage through all media outlets? Instead of taking away such an easy tool to fight the virus?
In Taiwan they gave instructions on TV for the population how to disinfect surgical masks. In China instructions were given too.
I don´t understand this, too…