A review of eight studies published in the British Medical Journal has shown that wearing a face mask reduces the risk of contracting COVID-19 by 53%. The result was similar for hand-washing. Physical distancing; however, reduced the risk by a quarter.

The researchers looked at 72 studies of COVID-19 precautions during the pandemic and eventually reviewed 8 studies on handwashing, mask wearing and physical distancing. In 6 studies that evaluated mask wearing, there was a 53% reduction in COVID-19 cases. In 5 studies that evaluated physical distancing, a 25% reduction in the rate of COVID-19 was found. 

Additionally, handwashing was also found to be associated with a considerable reduction in COVID-19 cases of up to 53%. However, in adjusted models, the results were not statistically significant… (NDTV – Bloomberg; Medscape, November 19, 2021)