The Food and Drug Administration on Wednesday authorized new Covid-19 vaccines for emergency use for the first time since the original vaccines were approved in December 2020. The new boosters from Pfizer/BioNTech and from Moderna are targeted at the BA. 4 and BA. 5 subvariants of the omicron variant. They’re also the engine of a new vaccine booster campaign in the United States as health officials brace for another surge in cases.
“As we head into fall and begin to spend more time indoors, we strongly encourage anyone who is eligible to consider receiving a booster dose with a bivalent COVID-19 vaccine to provide better protection against currently circulating variants,” said FDA Commissioner Robert M. Califf in a statement.
“Bivalent” refers to the fact that the vaccines contain genetic instructions for the immune system to target the original version of the SARS-CoV-2 virus that causes Covid-19, as well as the main variants in circulation now. The BA. 4 and BA. 5 subvariants are notorious for evading prior immunity to Covid-19, although older Covid-19 vaccines are still preventing hospitalizations and deaths from newer versions of the virus.
Before those shots can start going into arms, the Centers for Disease Control and Prevention has to weigh in and come up with guidelines for how to distribute these new shots. Advisers to the CDC are meeting this Thursday and Friday to come up with recommendations. Meanwhile, the US government has already ordered 170 million doses. Shots could start rolling out next week, subject to approval by the CDC.
As for who is eligible, the Moderna bivalent vaccine is available to anyone over the age of 18 as a first booster or a second booster, provided it’s been at least two months since the last shot. The Pfizer/BioNTech vaccine follows the same criteria except that it’s open to people ages 12 and up.
It doesn’t matter what vaccine you used as your first doses of boosters. The bivalent vaccines can only be used as boosters and are not intended to replace any of the existing vaccines.
Officials didn’t specify whether the eligibility window is different for people who were recently infected with Covid-19, but researchers have found that surviving an infection can increase protection against reinfection. “A Covid infection in a vaccinated person — essentially, that functions as a booster,” Andrew Pekosz, a professor of microbiology and immunology at Johns Hopkins University, told Vox earlier this month. “So you probably don’t need to get a booster for anywhere from three to six months after your Covid infection.”
While the rate of Covid-19 deaths in the US has fallen sharply from its peak this past winter, deaths are still holding steady at roughly 400 per day. This is because social distancing and mask mandates are virtually gone. The virus has more potential to spread. These new variants can jump between people. People with weaker immune systems (e.g., older people and individuals with preexisting conditions) are at greatest risk of dying. People who have had their vaccines for months may not be as immune to new infections.
Health officials hope that the new boosters formulated to target the latest variants will keep a lid on hospitalizations and deaths this fall. But boosters are only effective if people actually get them, and it’s clear not everyone is ready to roll up their sleeves. About one in five people in the US have not received any dose of a Covid-19 vaccine, and among those who are vaccinated, less than half are boosted. If the uptake of the bivalent vaccines is similarly low, they may not do much to stem the losses of another Covid-19 surge. And as long as the virus spreads, it mutates, increasing the chances of another dangerous variant emerging.
Some researchers have pointed out that the reformulated vaccines are only marginally better than the original versions of the shots, so they question whether it was worth holding out for them. Again, while the original versions of Covid-19 vaccines don’t hold off infections as well from the new variants, they still prevent most hospitalizations and deaths. It’s not yet clear if vaccines need to be updated on a routine basis. This depends on the evolution of the virus and its impact on public health. Scientists are also studying universal Covid-19 vaccines that could potentially protect against future variants. Those vaccines are likely years away, but they could become the last shot most people would need.
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