In Bangladesh, mask-wearing reduced COVID-like illness, cluster-randomized controlled trial shows

Proper mask-wearing increased and led to reduced COVID-like illness in villages in Bangladesh where masks were distributed and promoted, reports a cluster-randomized controlled trial. The trial – which spanned nearly 600 villages and encompassed approximately 340,000 adults – ran from November 2020 to April 2021, and its results, say the authors, suggest that mask distribution and promotion is a scalable and effective method to reduce symptomatic SARS-CoV-2 infections. While vaccines may constrain the spread of SARS-CoV-2 in the long-term, it is unlikely that a substantial fraction of the population in low- and middle-income countries will have access to vaccines before the end of 2021. Developing scalable and effective means of combating COVID-19 is thus of first-order policy importance. Inspired by the growing body of scientific evidence that face masks have the potential to slow the spread of the disease and save lives, Jason Abaluck et al. conducted a cluster-randomized controlled trial covering 342,183 adults in 600 villages in rural Bangladesh with the dual goals of (a) identifying strategies to increase community-wide mask-wearing, and (b) tracking changes in symptomatic SARS-CoV-2 infections as a result of their intervention. Colored masks of various construction – cloth or surgical – were handed out, accompanied by a range of mask-wearing promotional activities. For example, villagers were provided with information about the importance of mask-wearing and stopped on the street by mask promoters if they were not wearing masks to be reminded why they should. Local leaders also helped to encourage mask-wearing at mosques and markets. Abaluck et al. discovered mask-wearing averaged 13.3% in villages where no interventions took place but increased to 42.3% in villages where in-person interventions were introduced. In the latter village, the authors also observed a reduction in reporting COVID-like illness, particularly in high-risk individuals. The reductions were larger still – especially for symptomatic seroprevalence – in communities where surgical masks were distributed.  The results are relevant for mask dissemination and promotion campaigns planned in other countries, the authors say.