(CNN) — COVID-19 vaccinations have slowed to a trickle in some states, leaving unvaccinated Americans vulnerable to new variants and threatening the chances of reaching herd immunity.
The US reached its peak of daily vaccinations on April 1, with more than 4.3 million people inoculated in one day, according to data from the US Centers for Disease Control and Prevention.
Since then, the numbers have plummeted. Over the past week, an average of roughly 560,000 Americans have been vaccinated each day.
Mississippi is the state with the lowest percentage of its population fully vaccinated — 27.5% as of Monday, according to the US Centers for Disease Control and Prevention.
The state fell from 128,841 doses administered during the week ending March 27 down to 24,374 doses in the week ending June 5.
Alabama has the second-lowest percentage of fully vaccinated residents among all states — 29.4% as of Monday, according to CDC data.
The state fell from 44,397 doses administered April 8 down to 1,465 doses on Saturday, according to the Alabama Department of Public Health’s Covid-19 dashboard.
Arkansas, Louisiana and Tennessee and Wyoming also had less than 33% of their populations fully vaccinated as of Monday.
“I understand that in the short run we may get away with it, having slow vaccination rates,” said Dr. Ashish Jha, dean of the Brown University School of Public Health.
“But those people really are vulnerable — once we have more variants circulating in the United States — to get reinfected and potentially get very sick.”
Even those who’ve already had coronavirus should get vaccinated because research shows immunity achieved through vaccination is better than immunity through previous infection, said Dr. Anthony Fauci, director of the National Institute of Allergy and Infectious Diseases.
“We need to get vaccinated because vaccines are highly efficacious. They are better than the traditional response you get from natural infection,” Fauci said last month.
Lab research shows those who previously had Covid-19 and received two doses of an mRNA vaccine “had interesting, increased protection against the variants of concern,” he said.
And those relying on their immunity from previous infection need to understand the danger of new variants, Jha said.
“This is a bit of a misunderstanding that unfortunately a lot of people have … this idea that if you’ve been infected that you have natural immunity that you don’t need to get vaccinated,” Jha said.
“There is no doubt about it in my mind that a vaccine-induced immunity is much more durable and is going to hold up much better against the variants.”
Right now, the three vaccines used in the US work well against known variants of concern. But as coronavirus keeps spreading and mutating among unvaccinated people, “there may be future variants for which we are not so lucky,” said emergency physician Dr. Megan Ranney, director of the Brown-Lifespan Center for Digital Health.
Rare breakthough infections have milder outcomes
While the Moderna, Pfizer/BioNTech and Johnson & Johnson vaccines are highly effective at preventing severe Covid-19, they’re not perfect at preventing infection.
But even those who get infected down the road after getting vaccinated will likely be less miserable than if they hadn’t gotten vaccinated at all.
CDC data published research Monday showing those who had rare “breakthrough” infections after one or two doses of vaccine had 40% less virus in their bodies and were 58% less likely to have a fever.
They also spent two fewer days in bed than unvaccinated Covid-19 patients, according to the study.
“The only way to be protected is to be fully vaccinated,” Jha said.
For those taking the Pfizer/BioNTech or Moderna vaccines, “This is why everybody needs a second dose.”
Moderna says 5-year-olds could get vaccine by the fall
On Monday, Moderna CEO Stéphane Bancel said its vaccine will likely be available to children as young as five by the early this fall.
“I think it’s going to be early fall just because we have to go down in age very slowly and carefully,” Bancel said at an event hosted on the social media platform Clubhouse.
The Pfizer/BioNTech vaccine has already been approved for children as young as 12. Moderna said it is testing its vaccine on children as young as six months.
Bancel said the process will take time as it determines the appropriate dosages for small children. “We anticipate data available in the September/October time frame,” he said.