UK COVID-19 variant now ‘most common lineage’ in US, CDC says

The variant of COVID-19 discovered in the United Kingdom has become the most common linage in the United States, according to the U.S. Centers for Disease Control and Prevention.

During the White House’s COVID-19 briefing Wednesday, CDC Director Rochelle Walensky said the agency’s most recent estimates indicated the shift.  

"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," she said.

She said the shift is coming alongside data that suggests children and younger adults are becoming more prone to infection and severe illness.

"Across the country, we’re hearing reports of clusters associated with daycare centers and youth sports. Hospitals are seeing more and more younger adults, those in their 30s and 40s, admitted with severe disease," Walensky said. "Data suggests this is all happening as we’re seeing increasing prevalence of SARS-CoV-2 variants, with 52 jurisdictions now reporting cases of variants of concern."

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 As of April 7, more than 16,200 total cases of B.1.1.7 have been reported since it was first detected in the U.S. in December, data from the CDC shows.

According to data collected by Johns Hopkins University, the United States has more than 30.8 million confirmed COVID cases across all lineages — the most in the world. As of April 7, the U.S. also leads the world in deaths at more than 556,000.

On Wednesday, Walensky also noted that while vaccine rates are steadily increasing across the U.S., so are trends in both case numbers and hospitalization rates.

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The exterior of the Center for Disease Control (CDC) headquarters is seen on October 13, 2014 in Atlanta, Georgia. (Photo by Jessica McGowan/Getty Images)

"These trends are pointing to two clear truths: One, the virus still has hold on us — infecting people and putting them in harm’s way and we need to remain vigilant. And two, we need to continue to accelerate our vaccination efforts and take the individual responsibility to get vaccinated when we can," Walensky said.

Last week, the CDC announced more than 100 million Americans have received at least one dose of a COVID vaccine that prevents severe illness and hospitalizations.

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Both Pfizer and Moderna have said their product remains highly effective in combatting the variants.

Dr. Anthony Fauci, the nation’s top infectious disease expert, said he feels confident in current indications of the enduring efficacy of COVID-19 vaccines. And he agreed that the vaccines provide protection against the B.1.1.7 linage.

Even so, he said variants of the virus present a worrisome "wild card" when factoring into the calculation of whether booster shots will be needed down the road.

RELATED: Fauci says variants are ‘wild card’ in COVID-19 booster vaccine equation

Should booster shots become necessary, Fauci said the United States will have plenty of doses stockpiled for quick distribution.

"We’re going to be stockpiling enough vaccines to be able to give boosters to people," Fauci told FOX Television Stations on Tuesday. "We’re also doing some clinical trials to see if you boost, what happens to the level of total antibodies, what happens to the level of antibodies against the variant, so we’re anticipating the need to be able to adjust to these variants that might arise, and we’re doing the clinical trials as well as purchasing more vaccine in case we do have to boost people."

This story was reported from Atlanta.