SACHA PFEIFFER, HOST:
After a massive surge this fall and winter, new daily coronavirus cases in the U.S. have dropped dramatically and COVID hospitalizations have plummeted by more than 50,000 in under a month. Will Stone reports on what experts think is going on.
WILL STONE, BYLINE: The waning winter surge is not a mirage. The last time cases were this low, it was the beginning of November. When Dr. David Rubin looks at pandemic numbers across the U.S....
DAVID RUBIN: It's hard to find a county that has me concerned. That's pretty striking.
STONE: Rubin runs the COVID modeling group at Children's Hospital of Philadelphia. He says respiratory viruses typically surge during colder months and then begin to wane. And coronavirus appears to be doing the same.
RUBIN: We're not out of the woods yet, but we're seeing a natural curve here over winter that reflects the seasonality of this virus.
STONE: But that doesn't explain everything. In some places, people are being more careful. In others, there's higher immunity because so many people got infected.
RUBIN: And so it plays out very locally. But we've reached this equilibrium, and now we have these factors that are playing into our favor.
STONE: Those factors include longer days, warmer temperatures, at least in some parts of the U.S., and not as many big national holidays. And about the holidays, Ali Mokdad at the University of Washington has some good news.
ALI MOKDAD: Americans did really behave during the holidays.
STONE: Yes, there were still millions of people who flew. But Mokdad says the metrics they track show people not only traveled less, but they seemed to stay put once they got somewhere.
MOKDAD: The week after Thanksgiving, dead silence. Even cellphone calls went down.
STONE: Now, clearly, some places did have a spike due to travel and family gatherings. But generally, the so-called surge on top of a surge was not as bad as expected. Mask wearing, social distancing, Mokdad says those improved as the situation got more dire in America's hospitals. The question is...
MOKDAD: Will Americans behave the same way as the cases are coming down? Because they behaved well when the cases were going up.
STONE: It's difficult to rank what is most responsible for the nationwide drop in infection. But Natalie Dean at the University of Florida sees behavior as a major reason.
NATALIE DEAN: Just the speed at how quickly things are turning around, that, to me, indicates that people may be responding a bit to what they see locally in their communities, what they're hearing on the news.
STONE: Millions of people getting vaccinated helps. But Dean says it's still early for that to be having a huge impact. Dr. Sarita Shah at Emory University agrees.
SARITA SHAH: Even though the numbers have been decreasing, there are several things that could very quickly send the cases soaring again.
STONE: That would be too quickly relaxing restrictions just as new, more contagious variants of the virus pick up speed in the U.S.
SHAH: You know, this is not the time to get complacent and lower our guard.
STONE: She says cases and hospitalizations are still way higher than they were during last summer. At Larry's Tavern in Seattle, owner Joel Stedman is hoping the positive trend continues. His bar was closed for months and just reopened a few weeks ago but only at the 25% capacity the state allows.
JOEL STEDMAN: We're not here to scare anybody off - just fill up the handful of tables we have and make sure it's a good time for those that are here.
STONE: Sitting in the booth with Joel is his wife, Margo.
MARGO: We've closed down and started up and closed down and gotten our hopes up and been let down so many times that we are cautiously optimistic.
STONE: The lull has the Stedmans dreaming of late spring and summer, what Joel thinks of as...
STEDMAN: I call it normal adjacent. And I think that with vaccine rollout, you'll start to see consumer confidence rising slowly but surely.
STONE: So far, more than 33 million Americans have received at least one shot of coronavirus vaccines. For NPR News, I'm Will Stone.
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