Understanding mix-and-match COVID-19 boosters

Updated Jan. 10, 2022

The Food and Drug Administration and Centers for Disease Control and Prevention have made booster recommendations for all three COVID-19 vaccines available in the U.S., including authorizing a mix-and-match option for booster shots from Johnson & Johnson (J&J), Moderna or Pfizer:

• Pfizer
  Are age 12 and older and it's been at least five months after completing the primary series; ages 12–17 may only get a Pfizer booster
  

  Are age 5–11, it's been at least 28 days after completing the primary series, and you are moderately or severely immunocompromised

• Moderna
  Are age 18 and older and it's been at least five months after completing the primary series
• Johnson & Johnson
  Are age 18 and older and it's been at least two months after receiving the Johnson & Johnson vaccination

"What mix-and-match means is that, regardless of what you got for your primary series, you could get any of the other three vaccines available for use in the U.S. as your booster if you're eligible for a booster," says Dr. Gregory Poland, head of Mayo Clinic's Vaccine Research Group.

So how do you know which booster vaccination to choose?

"All of the boosters will dramatically boost your antibody response," says Dr. Poland. "I would make the decision about a booster based on how did you respond to whatever you got originally? And are there any unique risk factors that you have?"

People who responded well to the first vaccine with minimal side effects can choose to get the same brand for their booster vaccination. But there are reasons someone might choose a different vaccine. For example, a younger man who initially got the Moderna or Pfizer vaccine might want a J&J booster, because the Moderna and Pfizer vaccines are linked with a slight risk of heart inflammation called myocarditis. And a woman under 50 might prefer to get a Moderna or Pfizer booster because the J&J vaccine is linked with a slightly higher risk of a rare blood clotting condition in younger women.

Watch a Mayo Clinic Q&A video about understanding mix-and-match COVID-19 boosters:

Information in this post was accurate at the time of its posting. Due to the fluid nature of the COVID-19 pandemic, scientific understanding, along with guidelines and recommendations, may have changed since the original publication date.