Should You Wear a Mask Again? What to Know During the Summer Surge

A high-quality mask “does wonders in terms of protecting you from getting infected, but you have to wear it the right way,” Dr. Pekosz said. “If you don’t crimp the metal thing around your nose, if it’s loose around you, then you’re probably breathing around the mask, not through the mask. And that is not going to protect you.”

Some experts estimate that you can use a mask for a total of about 40 hours before it’s time to replace it. If you notice fraying, creases, new holes or dirt on your mask, you should replace it before then, Dr. Marr said. If your mask is uncomfortable, or if you feel like it’s moving too much across your face, Dr. Marr recommends trying different brands to find the best fit.

Do you need to mask after being exposed?

If you get the dreaded text that someone you recently spent time with has tested positive for Covid, the C.D.C. recommends putting on a high-quality mask as soon as possible, and keeping it on for 10 full days when you’re around other people. Even if you test negative, the agency says you should still wear a mask in public indoor settings. It can take several days for people to develop symptoms, Dr. Pekosz said, and testing too early can lead to false negatives.

Is one-way masking effective?

Even if you’re the only person wearing one on the subway or in your office, a high-quality mask can still meaningfully reduce your risk of getting infected. “You’re going to be pretty well protected,” said Dr. Yvonne Maldonado, a professor of global health and infectious diseases at Stanford Medicine, because you’re guarding your face from the particles around you.

There are additional ways to build up your defenses against the virus: sanitizing your hands before touching your face, social distancing from others and getting an updated booster shot when the new vaccines are available.

While many people are exhausted by this long pandemic, Dr. Maldonado stressed it’s important to remember that we have tools to reduce our risk. “Masks work, period,” she said. “Whether you choose to use them or not is a different matter. But they definitely work.”