British Medical Journal: Mask Wearing Reduces SARS-CoV-2 Incidence by 53 Percent 
an extremely effective precaution against SARS-CoV-2 infection unrelated to vaccines, and reduces the incidence by 53 percent. The study is published in one of the leading scientific journals, the British Medical Journal.
Researchers conducted a meta-analysis of previous scientific work to determine the overall effectiveness of public measures to prevent coronavirus infection, such as wearing masks, social distancing and washing hands. The analysis included eight scientific studies that showed a 53 percent reduction in the incidence of COVID-19 associated with hand washing, thanks to wearing masks by 53 percent and social distancing by 25 percent.
A total of 72 studies reviewed. , 35 of which assessed the effectiveness of individual prevention measures, and 37 – the effectiveness of the entire set of measures. However, due to the heterogeneity of the data, a meta-analysis of the results on the effectiveness of measures such as quarantines, lockdowns, closings of borders, schools and workplaces was not possible.
Research in the United States showed that school closings reduced the incidence by 62 percent, and mortality – by 58 percent. However, Japanese scientists have not found such a connection. Saudi Arabia reported a 4.9 percent drop in COVID-19 incidence eight weeks after quarantine. Scientists in India have recorded that in the absence of quarantine, the risk of SARS-CoV-2 transmission increased 14 times. Research in the United States showed that job closings reduced transmission by 12-16 percent. A South African study found that general isolation reduced the risk of morbidity by 14.1 percent.