UK Variant Now the Dominant COVID-19 Strain In US

Lindsay Kalter

April 07, 2021

Editor's note: Find the latest COVID-19 news and guidance in Medscape's Coronavirus Resource Center.

The highly transmissible and deadly U.K. coronavirus strain, B.1.1.7, is now the most common form of COVID-19 in the United States, said Rochelle Walensky, MD, director of the Centers for Disease Control and Prevention.

"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 at a Wednesday press briefing. "The virus still has a hold on us, infecting people and putting them in harm's way, and we need to remain vigilant."

The development is mostly consistent with CDC's predictions. In January, the agency forecasted a takeover by the U.K. variant by March.

Because the strain is so powerful, it has led to a rise in cases among younger populations from activities like youth sports, Walensky said – particularly in states like Michigan where numbers are spiking.

"We are working closely with the state of Michigan and state health officials there. We have CDC teams on the ground working to assess outbreaks at correctional facilities. We're working to facilitate increased testing that's happening on the ground in the context of youth sports. We're doing more surveillance and sequencing so we can understand what's happening with B.1.1.7 and variants," Walensky said.

She added that the CDC is encouraging state officials to send more vaccine doses to areas where rates are especially high.

Walensky also advised that communities where transmission is high should not hold large events or indoor youth sports.

Meanwhile, studies continue to show the long-term effectiveness of COVID-19 vaccines, according to top coronavirus expert Anthony Fauci, MD.

According to a study out this week in the New England Journal of Medicine, antibodies from the Moderna vaccine remained high among 33 adults of varying ages six months after the second dose.

Although the study only looked at Moderna's vaccine, Fauci said "there's every reason to believe that similar results will be seen with the Pfizer as well as the J&J."