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Updated COVID-19 booster vaccines are here. Here’s what you need to know.

On September 1, the Centers for Disease Control (CDC) recommended the newly updated COVID-19 booster vaccines. Here are some frequently asked questions about the vaccines, eligibility, and more.

Where can I get the vaccine?

While the new vaccine is not available at MIT Medical at this time, it is readily available at many retail pharmacies and community health centers. You can search by location at vaccines.gov.

What’s the difference between the new COVID-19 booster shots and the original COVID-19 vaccines?

Previous COVID-19 vaccines, both initial shots and boosters, were monovalent. This means that they were formulated to protect against only one version of the SARS-CoV-2 virus — the original viral strain that was isolated and sequenced after emerging in late 2019 in Wuhan, China. The newly approved vaccines are bivalent. They contain mRNA that encodes for the spike protein of the original Wuhan strain and the identical spike protein found in both Omicron BA.4 and BA.5 subvariants.

Who is eligible to get one of the new booster shots?

The Pfizer-BioNTech booster is approved for individuals aged 5 or older; the Moderna booster is is approved for individuals aged 6 and older. Boosters are not currently recommended for children younger than 5. You may get a booster if you are otherwise eligible and it has been at least two months since you completed your initial vaccination series or got your last booster shot.

I’m eligible to get the new booster. Should I get it now or wait?

In most cases, the answer to this question will be “Get it now.” While you may be tempted to put off getting a booster until later in the fall for better protection through the winter, the CDC recommends that individuals get the booster as soon as they are eligible. Although it seems logical to expect a rise in cases during the winter months, the timing of past COVID-19 surges have been impossible to predict, and you can’t plan when you will be exposed to the virus. Unless you are recently recovered from a COVID-19 infection, the best strategy for most people will be to get boosted as soon as you can, so you will be optimally protected whenever you are exposed. 

What if I had COVID-19 over the summer?

According to the CDC, individuals who have recently recovered from COVID-19 may wait three months before getting boosted. That’s because, with a high level of circulating antibodies after recovering from your illness, you’ll likely have a less-than-optimal immune response to the booster if you get it too soon. And while those high antibody levels make it less likely that you’ll be reinfected in the three months following recovery, the CDC notes that factors such as your personal risk of severe illness or the level of illness in your local community could be reasons to get a vaccine sooner rather than later.

Is there a difference between the Moderna and Pfizer shots?

No, not in the ways that matter. There’s that difference in age criteria, but from your immune system’s perspective, it doesn’t really matter which one you get. Moderna’s booster is a bigger dose, which, past studies indicate, may generate slightly longer protection against infection but may also lead to more side effects. Both vaccines should provide similarly long-lasting protection from severe illness.

What kind of protection will the new shot provide, and how quickly?

Antibody titers will start to rise within days after getting the shot, but it will probably take a couple of weeks for you to reach peak immunity. Once antibody levels have peaked, you should have an enhanced level of protection against infection, at least for a few months. Longer term, the vaccines should provide continuing protection against severe disease. In addition, because the updated vaccines should produce broader immunity, they may provide additional protection against any new variant that might emerge.

Can I get my bivalent COVID-19 booster and my flu shot at the same time?

Yes. According to the CDC, you can get a COVID-19 vaccine and a flu vaccine at the same time if you are eligible and the timing coincides.

I heard that these boosters were approved without clinical trials; should that concern me?

No, not from the perspective of safety. These updated vaccines are manufactured the same way as the original COVID-19 vaccines, using the same ingredients. It’s the same way the annual flu shot is reformulated to match each year’s predominant strains. Unless flu-shot manufacturers make significant changes to the way they produce the vaccine, updated flu shots don’t require new clinical trials.

What we don’t yet have is real-world data on how well these updated COVID-19 boosters will actually perform. We’ll have that data in a few months, but while we wait, there’s no reason to delay getting a shot if you are eligible. And, encouragingly, data provided by both Moderna and Pfizer for earlier bivalent vaccines targeting BA.1 (approved last month in the U.K) showed that the shot was highly effective in preventing serious illness caused by the Omicron variant.

This news story has not been updated since the date shown. Information contained in this story may be outdated. For current information about MIT Medical’s services, please see relevant areas of the MIT Medical website.