Mask On

New research supports the shifting consensus about masks

On Friday, President Trump said that the CDC is encouraging people to wear masks in public, but that the measure is voluntary. The CDC has urged the administration to make this recommendation, reasoning that it would help prevent the wearer from unknowingly spreading disease.

The comprehensive guide to wearing masks published this week in Elemental outlined the two sides of the debate. Proponents of mask-wearing say that doing so would prevent people from inhaling or expelling virus particles in the form of aerosols — extremely tiny, airborne particles. Opponents point out that coronavirus is spread primarily through bigger droplets that don’t stay airborne, so masks are unnecessary and may cause more harm than good, like deprioritizing hand-washing and social distancing and giving people a false sense of security. There are also many different types of masks, complicating the debate.

We don’t yet know how the virus is transmitted, so there is no simple answer. But the research on how it moves is trickling in. Today in the journal Nature Medicine, researchers report that surgical face masks may effectively prevent the transmission of coronaviruses and the influenza virus. They based this conclusion on their study of 246 people with suspected respiratory infections and a big machine aptly named the Gesundheit II.

This machine collects the exhaled breath from sick people, allowing researchers to analyze what comes out. To use…