Centers for Disease Control and Prevention recommended Thursday that adolescents and adults receive updated booster shots from Pfizer or Moderna. The shots – also known as bivalent vaccines – are designed to target both the original strain of coronavirus and the omicron BA.4 and BA.5 subvariants currently in circulation.
The decision follows a similar recommendation from a group of independent CDC advisers, which voted in favor of the firings on Thursday.
The CDC’s recommendation means the injections can now be given to the public. But a spokesperson for the Department of Health and Human Services said people are unlikely to start receiving updated reminders until Labor Day.
After that, the availability of appointments should increase over several days, with appointments becoming more widely available within weeks, a senior administration official said. People will be able to search for the nearest sites offering updated boosters on Vaccines.gov.
Here’s what to know about the updated plans.
Are there enough doses for everyone?
White House officials have said the vaccine supply should meet demand this fall. The administration has purchased 171 million updated booster doses – 105 million from Pfizer and 66 million from Moderna – so far, with the option to purchase up to 429 million more.
Distribution of doses began after the Food and Drug Administration allowed shooting Wednesday, with shipments to tens of thousands of locations, including pharmacies. Prior to this, pharmacies, community health centers and rural health clinics could pre-order vaccines from the federal government.
A CVS spokesperson said its pharmacies expect to receive updated booster doses on a rolling basis over the next few days. People can book an appointment as usual on the CVS website or app.
Walgreens also said people can make an appointment to get updated boosters through its website or app or by phone.
For now, the shots remain free.
How are these boosters different?
While the initial Covid vaccine boosters only targeted the original strain of the coronavirus, the updated boosters are designed to add protection against the omicron subvariants. For this reason, Modified Plans will be the only boosters available for Teens and Adults going forward.
The newly authorized shots target the BA.4 and BA.5 sub-variants. As of Tuesday, BA.5 accounted for at least 87% of new cases in the United States. BA.4 and a similar subline, BA.4.6, accounted for approximately 11%.
“The updated Covid-19 boosters are formulated to better protect against the most recent Covid-19 variant in circulation. They can help restore protection that has waned since the previous vaccination and were designed to provide broader protection against newer variants,” CDC Director Dr. Rochelle Walensky said in a statement Thursday.
Pfizer and Moderna’s trials of their bivalent vaccines in humans investigated a formulation targeting the original omicron strain. The updated version, however, was tested in lab studies, which found that the boosters generated strong antibody responses against BA.4 and BA.5.
Laboratory tests “so far have been a very good predictor of the ability of vaccines to protect against infection, as well as protect against serious illness, hospitalization and death,” said David Montefiori, professor at the Human Vaccine Institute at Duke University Medical Center.
Who should get a callback?
The FDA has cleared Pfizer’s vaccine for people ages 12 and older and Moderna’s for ages 18 and older. For those who are up to date with their Covid vaccinationsthe updated booster constitutes a fourth, fifth or sixth injection, depending on age and health status.
But some vaccine experts question whether vaccines are still necessary for young, healthy people, given the lack of clinical trial data to demonstrate efficacy against the new omicron subvariants.
Still, Pablo Penaloza-MacMaster, assistant professor of microbiology-immunology at Northwestern University, said the potential benefits appear to outweigh the risks.
“The way I see it right now is that it looks like there’s not much to lose,” he said.
When is the ideal time for this reminder?
The CDC suggests that people are waiting at least two months since their last Covid shots to get the latest shots.
Older or immunocompromised people should be strengthened as soon as they meet these conditions, Montefiori said. But he suggested there would likely be more wiggle room in the schedule for younger, healthy people.
“The longer you wait to get the boost, the stronger the boosting effect will be,” he said. But for those who wait, he added, “there is this trade-off between waiting to get boosted to have a stronger boosting effect and the risk of getting infected while you wait to get the boost.”
Montefiori, who is 68, said he received his fifth vaccine three weeks ago and plans to wait three months for his bivalent booster.
The The CDC advises that people who have recently had Covid consider delaying their boosters until three months after their symptoms started or, if they were asymptomatic, since their positive Covid tests.
Penaloza-MacMaster said his research suggests that healthy people of all ages could even wait six months between shots or as a result of Covid infections.
But Montefiori said it was unclear how long immune protection lasts after Covid infection.
“The best advice I would give people is to get the bivalent boost as soon as they are eligible for it, whether they have been infected or not, due to the uncertain nature of the extent to which this infection has really boosted your immunity,” he said.