SCOTT SIMON, HOST:
There are signs that the pandemic is headed in the wrong direction as the highly contagious delta variant spreads. Cases in the U.S. are going up, so are the number of hospitalizations and deaths. CDC Director Rochelle Walensky said in a briefing yesterday the trend is clear. Unvaccinated people are at risk. NPR health policy correspondent Selena Simmons-Duffin joins us.
Selena, thanks for being with us.
SELENA SIMMONS-DUFFIN, BYLINE: Morning, Scott.
SIMON: I gather numbers are going up but not necessarily everywhere.
SIMMONS-DUFFIN: Yeah, that's right, so Walensky says it's a little bit of a mixed picture. Cases are rising in some places like California and New York that have pretty good vaccination rates. But she says by far, the most spread is happening in places where not many people are vaccinated. In fact, she said, 97% of people who get so sick with COVID-19 that they have to be hospitalized are unvaccinated. Officials are concerned by these numbers and point out that sickness and death is avoidable. COVID-19 is now a vaccine-preventable disease, and people who've been holding out should get vaccinated.
SIMON: Do scientists know why the delta variant seems to be more transmissible than the original strain?
SIMMONS-DUFFIN: So actually, yes. I talked to virologist Angela Rasmussen about this. She's a research scientist at the Vaccine and Infectious Disease Organization at the University of Saskatchewan. And she pointed to a compelling preprint study out of China recently that showed people who were exposed to the delta variant got sick fast.
ANGELA RASMUSSEN: And on top of that, when they started to test positive, their viral loads were a thousand times higher than people who had been infected with a variant that had been circulating in 2020.
SIMMONS-DUFFIN: That suggests people infected with delta are shedding way more virus, which could explain why it's so contagious. Rasmussen says the good news is that it still transmits in the same way as the original strain, so all of those mitigation tools like masking and handwashing and social distancing - all of those still work to block delta. And the vaccines are still highly effective against this variant.
SIMON: Does this mean that vaccinated people don't need to worry right now? CDC guidelines still say that vaccinated people for the most part don't need to wear masks. Is that correct?
SIMMONS-DUFFIN: Yeah, that's right, but I would say CDC is a bit out of step with a growing chorus of health experts on this front who say it does make sense to wear masks indoors if you're going out in public. This is Helen Chu. She's a professor of medicine at the University of Washington.
HELEN CHU: I would, so I haven't stopped masking indoors. I live with unvaccinated children. I do not want to put them in a situation where I may transmit to them.
SIMMONS-DUFFIN: So even though the chances of getting very sick and dying from COVID-19 are very low for vaccinated people, the risk is not zero, and people can still get infected.
SIMON: Selena, does it seem like the CDC might take another look at those masking guidelines right now?
SIMMONS-DUFFIN: Right now it does not seem so. CDC is standing firm. When asked about it at the briefing yesterday, Walensky only said that in places that are hot spots where there's low vaccination rates, it may make sense for local officials to consider masking requirements until the vaccine campaign can catch up. But I should say that one large county, LA County, made that call this very week. An indoor mask mandate for everyone, including vaccinated people, goes into effect at midnight tonight, so we'll have to see if other places follow suit.
SIMON: NPR health policy correspondent Selena Simmons-Duffin, thanks so much.
SIMMONS-DUFFIN: Thank you. Transcript provided by NPR, Copyright NPR.
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