AILSA CHANG, HOST:
The U.K. is struggling to stop a new variant of the coronavirus, which appears to be more contagious. And record-breaking case numbers have driven Britain into another nationwide lockdown. Meanwhile, here in the U.S., states like California, Arizona and Rhode Island have staggering rates of infection, some of the highest in the world. And health officials are wondering, is the new variant, which has already been detected here in the U.S., behind this latest spike? NPR's Michaeleen Doucleff investigates.
MICHAELEEN DOUCLEFF, BYLINE: Right after U.K. scientists reported they found a variant of the coronavirus that looks more transmissible, scientists in the U.S. went looking for the variant across the country. Trevor Bedford is helping to lead this effort. He's a computational biologist at the Fred Hutchinson Cancer Research Center. He says scientists have detected the new variant here, so it's definitely circulating, but the levels appear to be very low.
TREVOR BEDFORD: A rough estimate from across the U.S. would be about 1 in 1,000 frequency. So about 1 in 1,000 COVID infections is due to the variant.
DOUCLEFF: That's only about 0.1% of all cases. But Bedford says he expects that percent to rise quickly. In England, the variant went from rare to dominating the outbreak in about three months.
BEDFORD: And so I'd roughly expect a kind of a similar timeline of three months out to go from initial arrivals in the U.S. in December to starting to kind of dominate the virus population in, say, March.
DOUCLEFF: So on the surface, that sounds like good news. It means the U.S. still has two months to slow down this new variant and prepare for it. But Bedford says the findings are worrying. They mean the dire situation already happening in some states isn't because of a more contagious virus.
BEDFORD: I think it's not at all really conceivable that this more transmissible variant is - has contributed to surging cases in the U.S. and the fall-winter wave. We're kind of - we're just barely getting started with it.
DOUCLEFF: Some communities are seeing packed hospitals and overstretched health care systems with a less-transmissible version of the virus. What's going to happen if a more contagious form starts to circulate widely, even dominate the outbreak? Right now, scientists don't believe the new variant is more deadly. And it's transmissibility doesn't appear to be much, much higher. One study suggests a person sick with the older version of the virus infects about 10% of people they come into contact with. A person sick with the new variant infects about 15%, so a rise of about five percentage points. That doesn't sound too bad, right? But remember; viruses spread exponentially. Case numbers grow faster and faster over time. They accelerate.
EMMA HODCROFT: If you then crank that exponential growth up to a steeper curve, you very quickly start infecting many, many, many more people than you would have beforehand. And even though the percent that end up in hospital or dying stays the same, you know, a small percent of a big number is a big number.
DOUCLEFF: That's Emma Hodcroft. She's an epidemiologist at the University of Bern in Switzerland. She says the U.S. needs to be thinking about how to minimize damage from this new variant right now.
HODCROFT: This is our early warning because by the time you have something spreading exponentially in your country, it is much harder to get it under control.
DOUCLEFF: She says what needs to be done will be different for each community. Activities that seemed relatively safe before, like outdoor dining, might not be as safe with the new version of the virus. She also says states can ramp up contact tracing for the variant, prepare for new restrictions, and focus on vaccinating people as quickly as possible. Michaeleen Doucleff, NPR News.
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