What to know about COVID vaccine boosters that target omicron

For the first time since the beginning of the COVID-19 vaccination campaign, Tampa Bay residents can get redesigned shots that target the latest coronavirus subvariants.

The Centers for Disease Control and Prevention on Thursday recommended updated boosters that take aim at BA.4 and BA.5, two fast-spreading omicron subvariants.

The vaccine rollout is expected to begin this weekend and early next week, though questions remain about their effectiveness. The federal government authorized the shots without data from human clinical trials.

The updated shots come as COVID-19 continues to kill an average of about 400 people a day in the United States, according to federal health officials. New infections in Florida have been falling, but Tampa Bay remains at high risk for the virus.

Here’s what Florida residents should know about the updated boosters.

Who’s eligible?

Everyone ages 12 and up is eligible for the new Pfizer-BioNTech booster — and adults can get Moderna’s — as long as it’s been at least two months since their last COVID-19 shot, whether that was a previous booster or their initial vaccination.

When should people get the booster?

It might be worth waiting longer than two months since your most recent vaccine to get the updated booster.

If someone gets boosted too soon after being infected — or too quickly after receiving a vaccine — they’ll lose out on the benefit of the booster because their antibody levels are already high, said E. John Wherry, director of the Institute for Immunology at the University of Pennsylvania.

“About every four to six months is the time to start saying, ‘OK, I should really make sure that I’m up to date with my immunity to this virus,’” Wherry said.

What makes these vaccines different?

The boosters take aim at BA.4 and BA.5, two omicron subvariants. BA.5 emerged earlier this year and is now the dominant strain in the U.S.

The shots are called “bivalent” boosters because they contain components that target the original COVID-19 strain and the BA.4 and BA.5 lineages.

Have the shots been tested in humans?

The federal government authorized the BA.4 and BA.5 boosters without reviewing data from human clinical trials.

Instead, regulators relied on data from human studies of earlier experimental vaccines aimed at BA.1, another omicron subvariant; the effectiveness of the existing COVID-19 vaccines; and tests of the updated shots in mice.

Regulators considered “the totality of the evidence” in deciding to OK the boosters, said Peter Marks, the vaccine chief at the U.S. Food and Drug Administration, during a briefing with reporters Wednesday.

The agency’s decision to move forward has sparked debate, with some health experts arguing that relying on mouse data might dissuade people from getting the updated booster.

Supporters of the decision, though, say it’s important to prepare for the fall and winter, when another COVID-19 surge is expected.

They also note the government uses rodent data when updating the flu vaccine each year.

Moderna has started a human trial for its booster. Last month, Pfizer-BioNTech said it expected to begin a study in August.

How effective are the updated boosters?

That remains unclear.

“This was one of those decisions (of), ‘Well, it’s likely to give us at least some marginal improvement over something that we already know works well,’” Wherry said. “They certainly aren’t expected to be worse than what we already have.”

The earlier COVID-19 vaccines “do a great job” at protecting people from serious illness, Wherry said, though he noted that mild breakthrough infections still occur.

The U.S. Food and Drug Administration says the updated boosters meet safety standards and are expected to provide increased protection against omicron.

Immunocompromised people and older residents — along with those who live with them — and individuals with comorbidities should get the new shots, Wherry said.

How many people will get boosted?

Health experts fear that demand for the updated shots will be weak, given the low interest in earlier boosters.

Less than 50% of people who have completed their initial vaccinations have received a booster in the U.S.

About 33% of the total U.S. population is boosted, while in Florida it’s roughly 28%.

“We need to do a better job of getting people to get a booster,” said Michael Teng, a virologist at the University of South Florida.

When will young kids be eligible?

Pfizer-BioNTech plans to ask federal regulators in early October to authorize an omicron booster for children ages 5 to 11. The companies are also working on updated shots for kids ages 4 and under.

Moderna said it plans to submit data on pediatric boosters “in the coming weeks.”

How can people get the shots?

Tampa Bay residents can use the federal vaccines.gov website to find locations offering the boosters.

CVS, Walgreens and Walmart plan to offer them. Publix didn’t respond to a request for comment.

As of Tuesday, providers in the state had ordered 51,100 booster doses “based on demand,” according to the Florida Department of Health.