At the moment, most vaccines appear to be effective against the variants. But public health officials are deeply worried that future iterations of the virus may be more resistant to the immune response, requiring Americans to queue up for regular rounds of booster shots or even new vaccines.

“We don’t have evolution on our side,” said Devi Sridhar, a professor of public health at the University of Edinburgh in Scotland. “This pathogen seems to always be changing in a way that makes it harder for us to suppress.”…

Until recently, B.1.1.7’s rise was camouflaged by falling rates of infection over all, lulling Americans into a false sense of security and leading to prematurely relaxed restrictions, researchers say.

“The best way to think about B.1.1.7 and other variants is to treat them as separate epidemics,” said Sebastian Funk, a professor of infectious disease dynamics at the London School of Hygiene and Tropical Medicine. “We’re really kind of obscuring the view by adding them all up to give an overall number of cases.”