What to Know About the New COVID Booster Shots

The reformulated vaccines are here.

Photo: Scotty Perry/Bloomberg via Getty Images
Photo: Scotty Perry/Bloomberg via Getty Images

While the U.S. may have led the charge to develop and deploy COVID vaccines, our efforts to get and stay fully vaccinated have not gone well. As the two-year anniversary of the country’s vaccine rollout fast approaches, the U.S. pandemic response seems stuck at a standstill while the coronavirus keeps adapting and spreading at a startling pace. The U.S. booster-shot drive has been a confusing mess from the start, and as of now, far too many Americans who are eligible for either their first or second booster have not gotten them, weakening the country’s wall of immunity that has so far prevented a big wave of hospitalizations and deaths despite a surge of new cases from more transmissible Omicron subvariants like BA.5. Increasing booster uptake, and expanding the protection those boosters offer by tweaking them for the new variants, is one way to reinforce the wall. Below is everything we know about the newly available reformulated booster shots and the Biden administration’s plan to distribute them.

What are the newly available booster shots?

The FDA on August 31 authorized bivalent booster shots from Pfizer and Moderna, and the CDC signed off on them a day later. The shots from both companies have been reformulated to better target the Omicron lineage of COVID variants, including the BA.5 subvariant, which is better equipped to evade immunity than any strain of the coronavirus yet seen.

When will they be available?

Reportedly within days.

Who is eligible for the new boosters?

The updated Pfizer-BioNTech booster has been authorized for everyone 12 and older. The updated Moderna booster has been authorized for everyone 18 and older. Everyone in those age groups who has completed their primary vaccination series (with any vaccine), as well as anyone who has already received one or two boosters since then and is now eligible for another — is eligible to receive the updated boosters.

If you are not vaccinated yet, can you get the new formula for your first series of shots?

No, the updated formulas are currently only available as a booster shot. The original formulas will still be administered for the primary series of shots.

Who should get a booster now?

In general, the CDC recommends that everyone 5 and older get their first booster shot if it has been at least five months since they completed their primary vaccination series, or at least three months if they are immunocompromised.

A second booster shot is recommended for everyone 50 and older, and anyone 12 and older if they are immunocompromised, provided it has been at least four months since they received their first booster.

People under the age of 50 are not yet eligible for second booster shots, unless they are immunocompromised.

So when will everyone, including people under 50, be eligible for a second booster?

Not until at least later this fall, if everything goes according to plan.

The Biden administration had considered expanding eligibility for second booster shots to everyone under 50 this summer, but is now reportedly going to hold off until after it has rolled out the reformulated booster shots.

According to the New York Times, some top officials on the administration’s COVID team, including White House pandemic response coordinator Dr. Ashish K. Jha and the country’s top infectious disease expert, Dr. Anthony Fauci, had this summer advocated for expanding eligibility for boosters immediately, on account of the ongoing surge of cases fueled by the BA.5 variant. Regulators at the FDA and CDC reportedly preferred waiting for the new vaccine formulas.

How are the updated shots be different from the current vaccines?

All of the currently available COVID vaccines are monovalent, which means they only target a single virus — in this case, the original strain of the novel SARS-CoV-2 coronavirus, which emerged in late 2019. The reformulated mRNA vaccines due from Pfizer and Moderna this fall are bivalent, targeting both the original strain and the Omicron strain that has become the dominant lineage of the virus. Simply put, half of the reformulated dose is the original COVID vaccine, and half is the updated vaccine that targets Omicron.

Multivalent vaccines are nothing new. The annually updated flu vaccine, for instance, is a quadrivalent formula targeting four different strains. The vaccines for human papillomavirus (HPV) are multivalent as well. Many scientists and public-health officials have long predicted that we would eventually end up needing annually updated COVID vaccines to defend against the evolving coronavirus.

Both Pfizer and Moderna have been working on bivalent COVID vaccines for a while now. They actually submitted reformulations for FDA authorization earlier this year that targeted the original Omicron strain, BA.1, but the government then asked them to instead come up with a new formula which also targets the newer Omicron subvariants, particularly BA.5. That strain, which is the latest king of the variant hill, has the most immune escape of any COVID strain yet seen and continues to fuel a massive ongoing wave of new cases in the U.S. and abroad.

In all likelihood, Pfizer and Moderna’s reformulated vaccines will offer better protection against BA.5 and hopefully against future descendants in the Omicron lineage — though the scientific debate over the utility of targeting just the Omicron lineage remains unsettled.

It’s also possible that the updated vaccines will do a much better job of preventing infection. In 2021, the COVID vaccines were initially amazingly effective at doing that, but have been less and less so as the virus has evolved. Now, breakthrough infections and reinfections are normal, which obviously helps fuel uncontained spread of the virus. The ability to more effectively block infection may end up being the most important benefit these reformulated vaccines offer for most people.

How many Americans are behind on their shots?

A lot. According to CDC data, more than a third of Americans over 50, who are considered a higher-risk group for severe COVID, have not gotten a first booster dose despite being eligible for one. And among Americans over 50 who are eligible to get a second booster, nearly 70 percent have not done so. Among people 65 and older, who are at even higher risk, more than 60 percent of those eligible have not gotten a second booster either.

To put the increased risk in context, the CDC has estimated that in May, before the rise of the BA.5 subvariant, people over the age of 50 who had only received one booster dose were four times more likely to die from COVID than people over 50 who had received a second booster dose.

And though skipping boosters is significantly less risky for people under 50, CDC data indicates that less than 37 percent of eligible Americans under 50 have gotten their first booster.

According to a recent analysis of CDC data by the Kaiser Family Foundation, 70 percent of Americans (228 million people) were not up to date with their COVID vaccinations as of July 21. (That number includes vaccinated people who have not yet gotten at least one booster, people who never completed their first series of vaccines, and people who remain unvaccinated.) A recent estimate from Harvard researchers pegged the figure even higher: 77 percent aren’t up to date with their vaccinations, including 66 percent of those 65 and older (45 million people):

Researcher Benjy Renton also highlighted the significant disparities from state to state:

Do current vaccine formulations still work against the current COVID strains?

For the most part, yes. Here in the U.S., the original-formula vaccines and boosters still appear to be remarkably effective at preventing serious illness, hospitalization, and death against all known strains of the coronavirus. But there has been evidence of reduced vaccine efficacy against the Omicron subvariants for people who are not up to date on their boosters. Most Americans are now undervaccinated, including a majority of seniors, who continue to suffer the brunt of the country’s severe illness and death from COVID.

It’s also worth noting that vaccine efficacy is not the only factor affecting real-world immunity on a person-to-person basis. Countless Americans now have hybrid immunity, meaning they are both vaccinated and have had COVID, so they’ve got combined protection from both. And many Americans have already had an infection from some strain in the Omicron lineage.

What if another big COVID variant arrives?

This gets at one of the biggest arguments against the updated vaccine strategy. There was no Omicron variant a year ago, when the Delta variant was the most dominant and worrisome strain in the world. The world’s first BA.5 wave hit South Africa in March, while the U.S. was still dealing with the BA.2 and BA.2.12.1 subvariants.

The coronavirus is evolving rapidly, with new strains emerging and rising to dominance faster than at any previous point in the pandemic. Will the next big variant be a descendant of BA.5 or some other continuation of the Omicron lineage, or will it be something completely different? A reformulated vaccine can target a new variant, but only a number of months after it appears, and the virus doesn’t sit still.

That doesn’t mean that it’s pointless to get boosted with a dose of the reformulated vaccine, even if there is a new variant by the time you can. But betting billions of dollars of scarce federal funding on a game of variant Whac-A-Mole is not without risk.

If you are eligible for a booster now, should you go ahead and get it or wait for the updated vaccines?

According to the Times, regulators are expected to recommend that anyone who is eligible for another dose right now should get it — not try to wait for the reformulated vaccines.

What about a Novavax booster?

Novavax’s long-delayed shot recently became the fourth COVID vaccine approved by the FDA for use in the U.S. It’s a traditional protein-based vaccine like the ones that have been used for the flu and other diseases for decades, as opposed to the mRNA vaccines produced by Pfizer and Moderna, or the adenovirus vector vaccine from Johnson & Johnson. That means Novavax’s vaccine triggers an immune response using a harmless version of the coronavirus’s actual spike protein, which cannot cause the COVID-19 disease, but does prompt the body to produce antibodies and T-cells which protect against the virus. The vaccine has only been approved by the FDA for use as a two-shot primary vaccination series; though the Novavax vaccine is also used as a booster in European Union, Japan, and Australia, it’s not approved for that here in the U.S. yet.

On reason Novavax might be a popular option as a booster shot is that it produced fewer side effects in clinical trials than the mRNA vaccines. Another reason is that the company has already indicated that its vaccine produces a broad immune response against all variants, including BA.5. It is expected to seek authorization for the use of its shot as a booster soon, and it also has variant-specific reformulations in the works, which the company says should be available toward the end of the year.

Does a recent COVID infection count as a booster?

The federal government does not currently factor prior infection into its vaccination or booster shot recommendations. A COVID infection definitely triggers an antibody response that confers a level of immunity, but the amount depends on a number of factors, including how much virus someone is initially exposed to, the length and severity of their illness, and possibly even which strain they were infected with. In addition, some infections and reinfections may be asymptomatic or go otherwise unnoticed. Research has generally shown that vaccines offer meaningfully higher protection than prior infection.

All that being said, hybrid immunity from both vaccination and prior infection undoubtedly provides more robust protection than either would on its own.

What’s else is in the Biden administration’s booster-reboot plan?

According to the White House, the administration is revamping its outreach to high-risk groups about booster-shot eligibility and the benefits of getting another jab. It will air more booster-shot PSAs during television shows popular with seniors. Pharmacies in the federal pharmacy network have agreed to expand their efforts to reach out to customers who are eligible for a booster. And the Centers for Medicare and Medicaid Services will offer support, including on-site resources, to the hundreds of U.S. nursing homes with booster rates below 80 percent. The CDC has also released a “booster calculator” on its website to help people determine when they should get an extra dose.

So far, the U.S. has purchased 171 million of the reformulated doses for the fall and winter booster campaign, enough for a little over half the population. The Department of Health and Human Services signed a $3.2 billion agreement with Pfizer to purchase 105 million doses of its updated shot for the fall booster campaign. The U.S. also has a $1.74 billion contract with Moderna to purchase 66 million doses of its updated shot. Both deals include the option for the U.S. to purchase a total of 300 million doses of each company’s reformulated vaccine, for a potential combined total of 600 million shots. The Biden administration says it was able to scrounge up the money for the initial Pfizer and Moderna orders, but has warned that it won’t be able to exercise its options to buy more unless Congress approves additional funding.

This post has been updated.

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What to Know About the New COVID Booster Shots