The B.1.1.7 variant, first identified in Britain, is now the source of most new coronavirus infections in the United States, the director of the Centers for Disease Control and Prevention said.
The number of deaths, however, continue to decline — potentially a sign that mass vaccinations are beginning to protect older Americans and other highly vulnerable populations.
“These trends are pointing to two clear truths,” Dr. Walensky said. “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 to take the individual responsibility to get vaccinated when we can.”
Federal health officials are tracking reports of increasing cases associated with day care centers and youth sports, and hospitals are seeing more younger adults — people in their 30s and 40s who are admitted with “severe disease,” Dr. Walensky said.
It is difficult for scientists to say exactly how much of the current patterns of infection are because of the growing frequency of B.1.1.7.
“It’s muddled by the reopening that’s going on and changes in behavior,” said Dr. Adam Lauring, a virologist at the University of Michigan.
But he noted that people were becoming less cautious at a time when they should be raising their guard against a more contagious variant. “It’s worrisome,” he said.
Scientists hope that vaccination will blunt any potential fourth surge.
“We knew this was going to happen: This variant is a lot more transmissible, much more infectious than the parent strain, and that obviously has implications,” said Dr. Carlos del Rio, a professor of medicine and an infectious disease expert at Emory University. In addition to spreading more efficiently, he said, the B.1.1.7 strain appears to cause more severe disease, “so that gives you a double whammy.”
“This is a stark reminder of how quickly the virus can spread and its serious impact, even among healthy, young athletes,” the team’s doctor, Jim Bovard, said in a statement.
Source: New York Times