An ER doctor shares 7 key places he still wears a mask — and explains why he didn't put one on at the US Open

• Dr. Jeremy Faust, an emergency-medicine physician, says he doesn't think he's ever had COVID-19.
• In a recent blog post, he details all the places he does and doesn't wear a mask.

Dr. Jeremy Faust, an emergency-medicine physician and instructor at Harvard Medical School, says he doesn't think he's ever had COVID-19.

If true, that puts him in a pretty small minority of people in the US. It's likely that fewer than 1 in 5 Americans has never had a COVID-19 infection, the Centers for Disease Control and Prevention recently estimated.

But, when Faust recently attended the US Open for the first time since the pandemic hit, he went maskless while he was seated in the stadium. As the doctor explained in a recent Inside Medicine blog post, he's now very strategic about where he does and doesn't wear his mask.

Even though some tennis players and commentators have been coming down with mysterious flu-like bugs from the tennis tournament this summer, Faust said he didn't wear a mask while in his seat at the Open because it was outdoors — and "not that crowded."

He also didn't wear a mask when dining indoors recently with friends, despite the fact that COVID-19 rates are ticking up nationwide right now. (On Labor Day, the White House announced First Lady Jill Biden had COVID-19.)

But there are still a few places Faust has decided it's worth continuing to mask up to prevent infection (whether from COVID-19 or some other virus that might be floating around). He told Insider that in general, he still prioritized masking in small, crowded spaces where the airflow was bad and also when he knew he was around sick people.

The places Faust told Insider he still wore his mask included:

• Airplanes, most of the time (with exceptions for eating and drinking)
• Other public transport, such as the New York City subway
• Rideshares such as Uber and Lyft (he rolls down the window if he's snacking or sipping coffee)
• Stuffy public bathrooms (Faust wore his mask when he went to the bathroom at the US Open, where the restroom was "indoors, crowded, and kind of gross.") Faust told Insider he also brought his mask to restaurants "just for the restroom" because they tend to be tiny spaces without much air movement
• The pharmacy because "that's literally where sick people go to pick up Paxlovid"
• The hospital, though he makes exceptions when he wants to say hello to a patient with his whole face or emphasize a point
• At home, when members of his family are sick with illnesses like COVID

"Putting on a mask in some crowded settings but not others is not a contradiction, nor is it virtue signaling, nor an exercise in futility; It is harm reduction," Faust said in his post. "Taking this measure (and upping my hand hygiene game) continues to help me avoid the sheer inconvenience of getting sick, to say nothing of any misery or health risks I may face."

He said he wouldn't feel "cheated by the universe" if he did catch the virus as a result of taking some more risks recently, such as going for a two-hour meal indoors with friends while in New York, where he said there was "no mask in sight."

Recent research does suggest that COVID-19 infection risks rise the longer you are exposed to someone who's sick with the virus, meaning he'd probably be more likely to get COVID-19 from a friend than a stranger at the US Open.

But Faust wrote that he still believed at least some of his good luck so far was because he'd been somewhat careful over the past three and a half years. "Picking my battles, and throwing on mask when doing so literally costs me nothing," he wrote.