Face mask trial didn't stop coronavirus spread, but it shows why more mask-wearing is needed

[DonViejo]

By KAREN KAPLAN SCIENCE AND MEDICINE EDITOR

NOV. 20, 20206 AM

Back in the early days of the COVID-19 pandemic, researchers in Denmark decided to conduct an usual experiment to test the infection-fighting power of face masks the same way they’d evaluate a potential vaccine or drug.

At the time, mask use was not recommended by Danish health authorities, and fewer than 5% of residents used them outside of hospital settings. Those conditions made it possible to conduct the first — and only — randomized controlled trial of the face coverings.

The researchers recruited more than 6,000 volunteers from around the country who spent at least three hours each day with people from other households and didn’t wear masks for their jobs. About half of these volunteers were chosen at random to receive 50 surgical face masks and were asked to wear them whenever they left home for the next month. The other half did not get masks and served as controls.

Overall, 95 of the 4,862 volunteers who made it to the end of the study became infected with SARS-CoV-2, the coronavirus that causes COVID-19. That’s an infection rate of just under 2%.

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https://www.latimes.com/science/story/2020-11-20/face-masks-didnt-stop-coronavirus-spread-in-danish-clinical-trial