Masks useless to stop viral transmission - May even increase transmission - CDC, May 2020
(wwwnc.cdc.gov)https://wwwnc.cdc.gov/eid/article/26/5/19-0994_articleMeta study compiling data of Influenza transmission, from over 70 years of studies and observations, under real-world conditions. Looking at actual infection rates. Not fancy slow-mo videos of cough droplets, which completely ignore what happens beyond the first two seconds after you cough.
Published by the CDC, just before the political winds changed. Still available.
In our systematic review, we identified 10 RCTs that reported estimates of the effectiveness of face masks in reducing laboratory-confirmed influenza virus infections in the community from literature published during 1946–July 27, 2018.
In pooled analysis, we found no significant reduction in influenza transmission with the use of face masks (RR 0.78, 95% CI 0.51–1.20; I2 = 30%, p = 0.25)
Various types of masks were used in different scenarios, including disposable masks, reusable cloth masks and surgical masks. All with same results. Because these masks were never meant to decrease viral transmission. They were intended only to keep blood spurts out of a surgeons nose and mouth, and his snot and spit out of the open wound he's cutting into.
Disposable medical masks (also known as surgical masks) are loose-fitting devices that were designed to be worn by medical personnel to protect accidental contamination of patient wounds, and to protect the wearer against splashes or sprays of bodily fluids (36). There is limited evidence for their effectiveness in preventing influenza virus transmission either when worn by the infected person for source control or when worn by uninfected persons to reduce exposure. Our systematic review found no significant effect of face masks on transmission of laboratory-confirmed influenza.
They still weaseled in that it "should" work "in theory" (even though none of the actual data supported that). But did concede that with improper use and disposal (which is all current use, as nobody is doing it right) masks actually made things worse:
In theory, transmission should be reduced the most if both infected members and other contacts wear masks, but compliance in uninfected close contacts could be a problem (12,34). Proper use of face masks is essential because improper use might increase the risk for transmission (39). Thus, education on the proper use and disposal of used face masks, including hand hygiene, is also needed.
Spoilers: The only thing that actually worked was washing your hands and general cleanliness, especially when it comes to food and toilets. Cultures and settings with poor hygiene habits saw far worse transmission rates.
