CDC Now Recommends Wearing a Mask in Some Cases

A physician explains the facts behind a new advisory to wear face masks in certain public settings

Wearing a mask is especially advised for crowded places like buses and subway cars. helloabc/Shutterstock

The Centers for Disease Control and Prevention has changed its policy and is now advising everyone, whether or not they have symptoms of COVID-19, to cover their face with a mask or cloth covering whenever social distancing is difficult to maintain. To be clear, the CDC is not saying you should wear a mask wherever you go, but rather in places where people congregate, including grocery stores and public transportation and ride-shares.

The shift in recommendations reflects growing evidence that COVID-19 can be transmitted by a person’s exhalations and normal speech but also the fact that people are not effectively covering their sneezes and coughs.

The Stealth Virus

COVID-19’s middle name should be “stealth.” People can be shedding virus for one to three days before showing any symptoms—including no coughing, sneezing or fever—in what’s called “presymptomatic transmission.” A Singapore study suggests that 10 percent of infections are attributable to presymptomatic spread.