A large, real-world study of face masks in Bangladesh has reestablished that masks play a role in limiting the community spread of COVID-19. 

The study also suggested that surgical masks are more effective than cloth face coverings. An important finding in the study is that mask wearing does not make people abandon social distancing, which public health officials had suspected might happen. The study included over 600 local governmental districts in Bangladesh and around 340,000 people. Half of the districts were given cloth or surgical face masks and were constantly reminded to wear them properly while the other half were followed with no intervention. In comparison with the villages that did not use masks, those in which any type of masks were worn reported around 9% fewer symptomatic cases of COVID-19, which was a statistically significant finding.

This could be an underestimation of the effectiveness of masks as the researchers only tested those who were having symptoms. This could have missed individuals with very mild or asymptomatic infections. Additionally, among those who developed symptoms, only a third underwent a blood test.

Researchers also noted that in villages where surgical masks were worn, there were 11% fewer COVID-19 cases compared to villages where masks were not worn. Furthermore, in villages in which cloth masks were worn, there was a mere 5% reduction in infections… (Medscape)