And the country now averages more than 3 million doses daily, according to CDC data.
But only about 18.5% of Americans are fully vaccinated, CDC data shows, and Covid-19 cases in the country have recently seen concerning increases.
“I do think we still have a few more rough weeks ahead,” Dr. Celine Gounder, an infectious diseases specialist and epidemiologist, told CNN on Sunday. “What we know from the past year of the pandemic is that we tend to trend about three to four weeks behind Europe in terms of our pandemic patterns.”
What’s worse, experts say, is that the variant is changing the pandemic’s playbook and could spell trouble for younger groups that haven’t yet been vaccinated.
“We have to think about the B.1.1.7 variant as almost a brand new virus,” said Dr. Peter Hotez, dean of the National School of Tropical Medicine at Baylor College of Medicine. “It’s acting differently from anything we’ve seen before, in terms of transmissibility, in terms of affecting young people, so we have to take this very seriously.”
More young people infected, hospitalized
The difference between previous surges and another possible surge now is “the people most affected now are the younger individuals,” emergency physician Dr. Leana Wen told CNN on Sunday.
“We’re seeing in places like Michigan that the people who are now getting hospitalized by large numbers are people in their 30s and 40s,” Wen said. “And now we’re even seeing children getting infected in larger numbers too.”
It’s not just Michigan.
“What we’re seeing is pockets of infection around the country, particularly in younger people who haven’t been vaccinated, and also in school-aged children,” former Food and Drug Administration commissioner Dr. Scott Gottlieb told CBS’s “Face the Nation” on Sunday.
“If you look what’s happening in Michigan, in Minnesota, in Massachusetts, for example, you’re seeing outbreaks in schools and infections in social cohorts that haven’t been exposed to the virus before.”
“The infection is changing its contours in terms of who’s being stricken by it right now,” he added.
And a third of all of the county’s Covid-19 hospitalizations were people younger than 45, according to Dr. Raul Pino, director of the Florida Department of Health in Orange County.
New Jersey officials said last week that variants, including the B.1.1.7 strain, were contributing to a rise in cases and hospitalizations — including in younger age groups.
Between the first and last weeks of March, there was a 31% and 48% increase in the number of hospitalizations among the 20-29 and 40-49 age groups, respectively, state health commissioner Judy Persichilli said Wednesday.
Meanwhile older residents only saw single-digit percent increases, she added.
How we can curb another surge of infections
Despite alarming warning signs, the US is not powerless, experts have stressed.
“We say it over and over again and we need the local people, we need the governors and the mayors and others to be able to say, we’re not out of it yet,” Fauci said.
“People say, ‘Well you just want to confine us forever.’ No, this is not going to last forever because every day that you get four million, three million people vaccinated, you get closer and closer to control.”
Hotez estimated Sunday that Americans need to hold on for “another four to six weeks, and then we’ll be on the other side of it.”
“All the vaccines seem to work just as well against this UK, B.1.1.7 variant … so that is really good news,” he said. “I have a lot of confidence that we’re going to be in a really good place by the summer.”
“But if you’re not vaccinated, you have to behave as though you’re highly vulnerable to this virus, this is not a time to get sick,” Hotez added.
CNN’s Naomi Thomas, Ganesh Setty and Heather Law contributed to this report.