STEVE INSKEEP, HOST:
Two numbers show the dramatic increase in the pandemic. This month, the number of coronavirus cases in the United States climbed sharply, reaching 200,000 per day. And in the month ahead, scientists estimate the country could easily have a record-breaking more than 400,000 cases per day.
Michaeleen Doucleff is NPR's global health correspondent and told us this morning that different cities are affected differently.
MICHAELEEN DOUCLEFF, BYLINE: Yes, so Washington, D.C., New York City, Chicago, San Francisco and Seattle are all seeing fast record-breaking surges. For instance, Chicago recently recorded nearly 10,000 cases in one day. And in D.C., cases have jumped more than fivefold in the last two weeks.
I talked to Dr. Robert Wachter at the University of California, San Francisco. He estimates that about 1 in 20 people in that city are walking around with COVID right now and don't even realize it.
ROBERT WACHTER: So that is pretty shocking. If you were in a room with about 30 or 40 people, there's almost a near certainty - about a 90% chance - that one of them has COVID. And so that's a little scary.
DOUCLEFF: Miami, Houston and New Orleans are also seeing big surges.
INSKEEP: Well, I got to tell you, as a resident of Washington, D.C., I can kind of tell this anecdotally. I'm surrounded by people - our, you know, family and friends - we're just getting constant reports of positive tests or people who are having to quarantine because of someone positive near them. There's a lot more of that than in the past.
DOUCLEFF: Yeah.
INSKEEP: But let me ask about the difference between positive tests and serious cases, hospitalizations. What's happening with them?
DOUCLEFF: Yeah. So in some cities, including New York, Washington, D.C. and Chicago, hospitalization rates are already rising, and that's expected to continue. But so far, hospitalizations aren't rising as quickly as cases.
Robert Wachter told me that over in San Francisco, doctors estimate with delta they would have seen two to three times more hospitalizations at this point than they're having with omicron.
INSKEEP: Why is that the case?
DOUCLEFF: Yeah. So right now, it looks like maybe two factors are at play. First off, Americans are starting to become partly immune to SARS-CoV-2, either through vaccinations or prior infections. The vaccine doesn't stop an infection with omicron, but it does reduce the risk of hospitalization by about 70%. And with a booster shot, the protection is even higher. Second, you know, there's growing evidence that omicron might cause slightly less severe disease than the delta variant.
Robert Wachter at UCSF says it's not much less severe - perhaps 10% to 20% - so a modest reduction.
WACHTER: If you're a person who has no immunity at all - no vaccination and no prior infection, or your prior infection was a year and a half ago and it was mild - you're not out of the woods. I mean, there is a reasonable chance that you will get very sick with omicron.
INSKEEP: So people who don't have the protection of vaccination still have to worry here.
DOUCLEFF: Yeah, absolutely. And remember, many hospitals in general are already overburdened. They're short-staffed. So even a smaller surge in hospitalizations could be crippling for hospitals and deadly for patients.
INSKEEP: What is this doing to the debate about even more booster shots?
DOUCLEFF: Yeah. So Israel announced last week they are going to start giving a fourth shot to older people and health care workers. But just this weekend, the government called off that campaign because of data showing that hospitalization rates with omicron are likely lower. And there is some concern among scientists that too many booster shots too quickly may backfire and cause the immune system to sort of go to sleep or start ignoring SARS-CoV-2.
INSKEEP: A good reason to proceed cautiously - Michaeleen, thanks so much.
DOUCLEFF: Thank you, Steve.
INSKEEP: That's NPR's Michaeleen Doucleff. Transcript provided by NPR, Copyright NPR.
