When Can You Get a Booster Shot?

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 5 years and older and at least five months have passed since you received your second dose.

Why Five Months?

The CDC is recommending boosters five months after the second dose of both 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.

Pfizer or Moderna Second Booster

Regarding a second booster dose, people 12 years of age and older with certain kinds of immunocompromise and all people age 50+ who have received an initial mRNA booster dose at least four months previously are eligible for a second booster dose.  

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—however, the CDC recommends both mRNA COVID vaccines over boosting with Johnson & Johnson.

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.

Johnson & Johnson Second Booster

Adults who have received a primary vaccine and a booster dose of Johnson & Johnson’s vaccine at least four months ago can now receive a second booster dose using an mRNA vaccine.

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.”

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.”

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.