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When Can You Get a Booster Shot?

Three ampules of COVID vaccines, two with purple caps.

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Key Takeaways

  • COVID-19 vaccine booster shots are now authorized for all adults in the U.S.
  • You are eligible for a booster shot if you are 18 years and older and completed the Pfizer or Moderna primary vaccine series at least six months ago OR received the Johnson & Johnson vaccine at least two months ago.
  • Individuals who meet eligibility criteria can choose any of the three authorized booster vaccines.


If you're wondering if it's time for you to get a COVID-19 booster shot, it depends on whether or not you meet eligibility criteria set by the Centers for Disease Control and Prevention (CDC), as well as how much time has passed since you received the final dose of your initial vaccine regimen.

There is a difference in timing that depends on whether you received either the Pfizer or Moderna vaccines or the Johnson & Johnson vaccine. Here's how to figure out if it's time for you to get a booster shot.

If You Got a Pfizer or Moderna Shot

If you originally received either of the mRNA vaccines, you can get a booster shot if you are 18 years and older and at least six months have passed since you received your second dose.

According to the Food and Drug Administration (FDA), the booster shot that you get does not need to be the same brand as the first vaccine that you got.

Why Six Months?

The CDC is recommending boosters six months after the second dose of one of the mRNA COVID vaccines because data on the vaccines' efficacy suggests that after that amount of time has passed, the vaccines start to offer less protection.

If You Got the Johnson & Johnson Shot

If you received the Johnson & Johnson vaccine, which only requires one shot, you need to wait at least two months before you can get a booster. You can get a booster shot of Pfizer or Moderna, or another Johnson & Johnson shot.

The CDC is recommending that everyone over the age of 18 who initially received the Johnson & Johnson vaccine get a booster shot.

Why Two Months?

CDC data on the J&J vaccine's performance in real-world conditions showed that it was only 71% effective at preventing hospitalization from COVID-19 in adults who did not have compromised immune systems. That's compared to Moderna, which was 93% effective, and Pfizer, which was 88% effective.

David Dowdy, MD, PhD, an associate professor of epidemiology at the Johns Hopkins Bloomberg School of Public Health, told Verywell that the two-month waiting period for a booster shot after getting a J&J shot is a bit arbitrary and that he thinks "it's based largely on when antibody levels tend to fall off from that initial 'pop' that you get."

Data that Johnson & Johnson reported on its vaccine efficacy showed that when boosters were given, antibody levels increased by four to six times what occurred when a single shot was given. That increase put it on par with the protection offered by Moderna and Pfizer's shots.

Less Urgency for Boosters

Dowdy said the reason booster shots are being recommended by the CDC now is that the vaccines' effectiveness wanes slightly after several months, though they are still effective at preventing severe COVID illness and hospitalization.

"The urgency to get a booster is not the same as the urgency to get the initial series for many people in the U.S. right now,” Dowdy said. “It's not that you have to run to the pharmacy and get the booster today, but it is recommended, and it probably does provide some additional protection.”

David Dowdy, MD, PhD

The urgency to get a booster is not the same as the urgency to get the initial series for many people in the U.S. right now.

— David Dowdy, MD, PhD

However, Dowdy thinks that among the general public, people who received the Johnson & Johnson vaccine should consider getting a booster shot, as "there is some evidence that one dose of the J&J vaccine is a little less effective than two doses of either Pfizer or Moderna."

One concern that Dowdy has is that the focus on getting booster shots may take attention away from getting more people vaccinated with their first round of COVID-19 vaccines.

“There are still a lot of people out there who haven't been vaccinated and who might be willing to get a shot,” said Dowdy. “The benefit of the first doses is much greater than the additional benefit of a booster.”

What This Means For You

You can get a COVID-19 booster shot if you are 18 years and older, and if six months have passed since your second Pfizer or Moderna dose, or if two months have passed since your Johnson & Johnson dose.

The information in this article is current as of the date listed, which means newer information may be available when you read this. For the most recent updates on COVID-19, visit our coronavirus news page.

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5 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
  1. Food and Drug Administration. Coronavirus (COVID-19) update: FDA expands eligibility for COVID-19 vaccine boosters. Published November 19, 2021.

  2. Food and Drug Administration. Coronavirus (COVID-19) update: FDA takes additional actions on the use of a booster dose for COVID-19 vaccines. Published October 20, 2021.

  3. Centers for Disease Control and Prevention. COVID-19 vaccine effectiveness for Moderna and Janssen vaccines. Published October 21, 2021.

  4. Self WH, Tenforde MW, Rhoads JP, et al. Comparative effectiveness of Moderna, Pfizer-BioNTech, and Janssen (Johnson & Johnson) vaccines in preventing COVID-19 hospitalizations among adults without immunocompromising conditions — United States, March–August 2021. MMWR Morb Mortal Wkly Rep. 2021;70(38):1337-1343. doi:10.15585/mmwr.mm7038e1

  5. Johnson & Johnson. Johnson & Johnson announces real-world evidence and phase 3 data confirming strong and long-lasting protection of single-shot COVID-19 vaccine in the U.S. Published September 21, 2021.