ATLANTA - CDC Director Rochelle Walensky says the more contagious B.1.1.7 strain of the coronavirus is now the dominant strain infecting Americans.
"Based on our most recent estimates from CDC surveillance, the B. 1.1.7. variant is now the most common lineage circulating in the United States," Dr. Walensky says.
The news comes as the US is averaging about 63,000 new infections and 5,000 hospitalizations a day, both up slightly from last week.
The country is averaging about 745 COVID-19 deaths each day, down just over19% from last week's average, she says.
Dr. Walensky says the B.1.1.7. strain is thought to be anywhere from 50 to 100% more transmissible than the other circulating strains.
It's also been linked to more severe disease and hospitalizations.
Health officials are closely tracking surges in the Northeast, Florida, California and Michigan, which is now averaging about 6,600 new COVID-19 infections a day.
"Across the country, we're hearing reports of clusters of cases associated with daycare centers and youth sports," Walensky says. "Hospitals are seeing more and more, younger adults, those in their thirties and forties, admitted with severe disease."
The US is vaccinating 3 million people a day.
Health officials say the 3 vaccines authorized in the US appear to work well against the B. 1.1.7. variant, and about 76% of Americans over 65 have had at least one shot of the vaccine.
ER visits and hospitalizations in older Americans are way down, a sign the vaccines are working to protect those most at risk of complications from the virus, Dr. Walensky says.
"That said, we're still seeing older people hospitalized, and it's the ones that have not yet been vaccinated," she says. "We're hearing stories of, you know, 'I got my vaccine yesterday and now I have COVID.'"
About 108 million Americans, or 40 to 45% of US adults, have now had their first dose of the vaccine.
"These trends are point to two clear truths: One, the virus still has a hold on us, infecting people and putting them in harm's way, and we need to remain vigilant," Walensky says. "And, two, we need to continue to accelerate our vaccinations and to take the individual responsibility to get vaccinated when we can."
After a major push in March to vaccinate teachers and childcare providers, health officials says 80% of school staff have now had at least one dose of the vaccine.
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