I heard National Institutes of Health director Dr. Francis Collins state that there many studies related to the effectiveness of mask on the CDC site. So, I went to the CDC site . What was found there is amazing.
I am not a “professional” scientific study expert. However, I did not find any planned study that compared a “control group”, with/without mask, vs “a “non-controlled group”, with/without mask.
The first on the list “Hendrix” investigated 2 symptomatically ill hair stylist with 139 clients found that none of the 67 clients that consented to an interview and testing developed infection. Think about that. 2 hair stylist and 67 clients are a scientific study.
The second “real-world” study cited was of 124 Beijing households with > 1 laboratory-confirmed case with mask use before symptoms reduced transmission to others in the households. Yeah, that’s it trust China.
The next was a “retrospective” study of 1,000 Thailand persons interviewed “of those who reported”.
The “Science Brief” states that a study of 382 young sailors of the outbreak aboard the USS Theodore Roosevelt, found that use of face covering on-board was associated with a 70% reduced risk. But actually, a look at the study, it says taking preventive measures such as face covering, avoiding common areas, social distancing and presence of antibodies contributed to reduced risk. The brief ignores a couple of things – young healthy adults and other preventive measures.
The “Rader” investigation was based on self-reported web-based survey. That is unbiased science?
The “Wang X” related to healthcare workers probably using N95 mask. Not general population and cloth mask.
The table of studies cited 15 investigations, of which the “Outcome” was Estimated Seven times. Many of these followed mandatory mask wearing by political dictate. So, the scientific outcomes are based on estimates and “could haves”.
Another interesting point in the “Science Brief”, is mask wearing has no significant adverse health effects. There was no change in oxygen or carbon dioxide levels while wearing a cloth or surgical mask. Among 12 healthy non-smoking adults, there was minimal impact. 12? Ugh
What is glaringly absent is the current surge in cases during the mandatory mask wearing in many states. The cases are going up but the mask are on!!!
Could it be that the mask mandate is pure political bureaucrat activist masquerading as scientist?

William J Stieren