Is It Time to Wear a Mask Again?

As new Covid variants gain traction, reinfections become more common and cases climb in certain areas, a few schools and businesses are reinstating mask requirements. Experts say it makes sense to increase precautions, including turning back to masks.

“I tend to say, if you’re going to go out, make sure you have a mask in your car, a couple masks at home or at work, so you always have something available to put on,” said Andrew Pekosz, a professor of molecular microbiology and immunology at the Johns Hopkins University Bloomberg School of Public Health.

Here’s a refresher on where, when and how to mask.

When should you wear a mask inside?

Everyone’s risk tolerance varies, Dr. William Schaffner, an infectious disease specialist at the Vanderbilt University School of Medicine, said. But particularly if you are 65 or older, have an underlying condition that makes you more vulnerable to severe disease or are pregnant, he recommends wearing a mask whenever you are in a relatively confined, crowded indoor space. That can include stores, offices and public transportation.

“Certainly every time you add another person to the room, particularly people who are within three to five feet of you, that increases your chance of getting infected, exponentially,” Dr. Pekosz added.

Time matters, too: Darting in and out of a packed grocery store is less risky than working all day in a busy office, for example. Ten minutes is a good marker to keep in mind, Dr. Pekosz said. If you’re headed somewhere indoors for longer than that, you may want to consider putting on a mask beforehand.

When should you wear a mask outside?

Outdoor transmission is generally rare, but if you’re in a scenario where people are “jammed together and yelling,” Dr. Schaffner said, like at a sporting event or a concert, you might want to wear a mask.