If You Got This COVID Vaccine, Get a Different Booster, New Study Says

New research shows that mixing and matching may benefit recipients of one shot.

More than 8.9 million people in the U.S. have already received a booster shot, according to the latest data from the Centers for Disease Control and Prevention (CDC). Both the U.S. Food and Drug Administration (FDA) and the CDC have approved additional shots for some Pfizer recipients, but officials have since warned Moderna and Johnson & Johnson recipients to wait until their respective vaccines are approved for booster shots, so that people can get another dose of the same vaccine. The FDA is set to discuss and vote on additional doses for these two vaccines on Oct. 14 and Oct. 15, but a new study has found that getting a different booster from your original vaccine might actually be beneficial in certain cases.

RELATED: If You Got Moderna or J&J, Dr. Fauci Says Here's When You Can Get a Booster.

White House COVID adviser Anthony Fauci, MD, recently told Bloomberg that a highly anticipated, nine-part study from the National Institutes of Health (NIH) and the National Institute of Allergy and Infectious Diseases (NIAID) on "the safety, the immunogenicity, and the ultimate efficacy" of mixing and matching COVID boosters had been completed.

The study, preprinted Oct. 13 on medRxiv, analyzed nearly 500 individuals who had received one of the three U.S. COVID vaccines—Pfizer, Moderna, or Johnson & Johnson—12 weeks before enrolling in the study, had no history of COVID infection, and were given a random booster shot of one of the vaccines.

According to the study, those who initially got the Johnson & Johnson vaccine were significantly better off when receiving a different booster. Johnson & Johnson recipients who received a Moderna booster had their neutralizing antibody levels rise 76-fold within 15 days, while a Pfizer booster raised their antibody levels 35-fold. A Johnson & Johnson booster only increased the levels 4-fold.

Nathaniel Landau, PhD, a microbiologist at the New York University Grossman School of Medicine, told NPR that the findings are clear: receiving a Johnson & Johnson booster after just one shot is "not as good" as receiving one of the mRNA vaccines as a booster. The other two boosters increased antibody levels 10 to 20 times higher than another Johnson & Johnson shot, which is likely a big enough increase to make a major difference in how much more protected someone is.

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In a response to the study, Johnson & Johnson said that it has "demonstrated that a booster of the Johnson & Johnson COVID-19 vaccine increases immune response regardless of a person's primary vaccination and confirm previously published data on the strong increase of immune response when the Johnson & Johnson COVID-19 vaccine is administered as a booster shot," per NPR.

Either way, officials have not yet given the official green light for mixing and matching booster doses. According to Fauci, while the study has been completed, the FDA is still reviewing it. "The data are being examined by the FDA … They will examine the safety, the immunogenicity—which means its ability to induce a particular immune response—and whether or not they will give an approval that you can use this product with that product, etc.," he said.

In addition to discussing Moderna and Johnson & Johnson boosters, the FDA is also set to confer on mixing and matching boosters. "The committee will hear presentations and discuss the available data on the use of a booster of a different vaccine than the one used for the primary series of an authorized or approved COVID-19 vaccine," the agency said in a statement.

RELATED: If You Got This COVID Vaccine, You Could Be Protected Longer, Study Says.

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