A large, randomized study from Stanford (Calif.) Medicine and New Haven, Conn.-based Yale offers the strongest evidence yet that wearing surgical masks can reduce community spread of COVID-19.
The eight-week study involved 342,126 people living in 600 villages in rural Bangladesh. Researchers randomly assigned participants to either a control or intervention group. The latter group received free masks that they were encouraged to wear, along with educational materials on why they were important, among other interventions.
Study participants who were encouraged to wear masks were about 11 percent less likely to contract COVID-19 compared to the control group. This percentage was even higher among older adults. People over age 60 were 35 percent less likely to get COVID-19 if they wore a mask.
"We now have evidence from a randomized, controlled trial that mask promotion increases the use of face coverings and prevents the spread of COVID-19," study author Stephen Luby, MD, a professor of medicine at Stanford, said in a news release. "This is the gold standard for evaluating public health interventions. Importantly, this approach was designed [to] be scalable in lower- and middle-income countries struggling to get or distribute vaccines against the virus."
The study is under peer review with Science, according to The Washington Post. Researchers released the findings online Sept. 1, because they consider the information "of pressing importance for public health" amid the pandemic, according to Stanford's news release.
To download the full study, click here.