Should You Mix and Match COVID Vaccines and Boosters? Here's What We Know

With COVID-19 booster doses now available from Pfizer, Moderna, and Johnson & Johnson, you may be wondering which brand you should get when it's time to book an appointment. Should you stick with the shot you had originally or choose to get a different brand for the booster?

In an October update to its COVID vaccination guidelines, the Centers for Disease Control and Prevention (CDC) declared it safe to mix and match vaccines and boosters. "Any of the COVID-19 vaccines can be used for booster vaccination, regardless of the vaccine product used for primary vaccination," the agency said. "When a heterologous or 'mix and match' booster dose is administered, the eligible population and dosing intervals are those of the vaccine used for primary vaccination." The Food and Drug Administration (FDA) also approved mixing the shots.

What Do Studies Say About Mixing COVID vaccines?

In a statement published on Dec. 30, Johnson & Johnson announced the results of a study conducted by Beth Israel Deaconess Medical Center (BIDMC), showing that the J&J COVID booster increased the antibody count in people who received the Pfizer vaccine by 41 times the amount. "Our analysis shows that a booster shot of the Johnson & Johnson COVID-19 vaccine generated a robust increase in both neutralizing antibodies and T-cells to Omicron," said Dan Barouch, MD, PhD, director of the Center for Virology and Vaccine Research at BIDMC.

In an October study, no severe adverse reactions were reported when mixing and matching COVID boosters. However, as The Washington Post pointed out, the research is still early and data is limited. Ultimately, experts recommend discussing the boosters with your doctor, who can help you make a decision based on your medical history. Beyond that, your choice in a booster shot may come down to what's most convenient.

"Part of the beauty of the mix and match is it enables people no matter where they are — rural or in the city — to have a choice," Kirsten E. Lyke, MD, one of the researchers who presented early findings to the FDA vaccine panel, told The New York Times. "They're all safe, they're all going to give you a boost, and they're all going to protect you against severe disease and death."

People 18 years of age and older who received the Moderna or Pfizer vaccines may be eligible for a booster shot six months after receiving their last dose. And those who've received the Johnson & Johnson vaccine are eligible two months after their initial vaccine, as long as they're 18 or older. The science is evolving, and the vaccine recommendations most certainly will as well. You can stay up to date on the CDC website.

— Additional reporting by Angelica Wilson