Who Is Eligible for a COVID-19 Vaccine Booster Shot—and When?

Hands reaching for the COVID booster shot vial.

Ellen Lindner / Verywell

Key Takeaways

  • COVID-19 vaccine booster shots are now authorized for everyone 5 years and older in the U.S.
  • Adults who meet eligibility criteria can choose any of the three authorized booster shots, although the Pfizer and Moderna mRNA COVID-19 vaccines are preferred.
  • Children and adolescents ages 5 to 17 are only eligible for the Pfizer booster.
  • Third doses of the COVID-19 mRNA vaccines are also authorized by the Food and Drug Administration (FDA) for some people five years and older who are immunocompromised.
  • Additional boosters are now recommended for certain individuals at increased risk for severe outcomes from COVID-19.

The Food and Drug Administration (FDA) has authorized a booster dose for everyone 5 years and older who completed their initial COVID-19 vaccine series. All three vaccines—Moderna, Pfizer, and Johnson & Johnson—have been authorized for boosters as of November 2021.

A third dose of the COVID-19 mRNA vaccines (Moderna and Pfizer) has also been authorized for immunocompromised people who meet specific criteria.

Additional booster doses are now recommended for certain immunocompromised individuals and all adults 50 and over.

Third Shots vs. Boosters

“Right now, the vaccines are still tremendously successful in preventing serious illness,” Aaron Eli Glatt, MD, FACP, FIDSA, FSHEA, the chair of medicine at Mount Sinai South Nassau in Oceanside, New York, and a spokesperson for the Infectious Disease Society of America, tells Verywell. 

Glatt says that because some immunocompromised people did not mount a good response to the vaccine, they need to get a third shot to ensure that they are protected.

For other fully vaccinated people, immunity wanes over time—which is why a booster shot dose might be beneficial. 

Additional Doses for Immunocompromised People

After reviewing the available data, the FDA authorized the use of a third dose of the Pfizer-BioNTech and Moderna vaccines for immunocompromised people 12 years and older in mid-August.

In January 2022, the FDA authorized an additional primary shot for immunocompromised children ages five and up.

“Those are people that never really mounted a good response,” says Glatt. “Studies show that if you give them an extra dose, [up to] 50% of them will mount a good response.”

Philip Felgner, PhD, the director of the Irvine Vaccine Research and Development Center at the University of California, Irvine, tells Verywell that immunocompromised people “are restricted from their movement around in the community when they’re concerned about being exposed to COVID in such a vulnerable position.”

The CDC’s Advisory Committee on Immunization Practices (ACIP) outlined the eligibility requirements for additional COVID vaccine doses.

A third dose is recommended for people in moderately to severely immunocompromised states either because of a medical condition or from taking immunosuppressive therapies, including: 

  • Active treatment for solid tumor and hematologic malignancies
  • Receipt of solid-organ transplant and taking immunosuppressive therapy
  • Receipt of chimeric antigen receptor (CAR)-T-cell or hematopoietic stem cell transplant (within 2 years of transplantation or taking immunosuppression therapy)
  • Moderate or severe primary immunodeficiency (e.g., DiGeorge syndrome, Wiskott-Aldrich syndrome)
  • Advanced or untreated HIV infection (people with HIV and CD4 cell counts <200/mm3, history of an AIDS-defining illness without immune reconstitution, or clinical manifestations of symptomatic HIV)
  • Active treatment with high-dose corticosteroids (i.e., ≥20 mg prednisone or equivalent per day when administered for ≥2 weeks), alkylating agents, antimetabolites, transplant-related immunosuppressive drugs, cancer chemotherapeutic agents classified as severely immunosuppressive, tumor-necrosis (TNF) blockers, and other biologic agents that are immunosuppressive or immunomodulatory.

The CDC says that an individual patient’s clinical team is best positioned to determine whether a third dose is appropriate, as well as when it should be given (within the recommendation that a third shot is received at least 28 days after completing a previous two-dose series).

To improve protection against severe COVID-19, booster doses of the mRNA COVID-19 vaccines are authorized for people 5 and over who are moderately or severely immunocompromised. A booster is recommended at least three months following completion of a three-dose primary vaccination series. A second booster dose is recommended four months after the first booster dose.

Those 18 and older who received Johnson & Johnson’s single-dose COVID-19 vaccine should get a second dose of an mRNA COVID-19 vaccine (Pfizer or Moderna), followed by an mRNA COVID-19 vaccine booster.

The CDC estimates that about 2.7% of U.S. adults are immunocompromised and are at a greater risk for developing a breakthrough COVID-19 infection despite being fully vaccinated.

About 44% of hospitalized breakthrough COVID-19 infections are in immunocompromised people.

Booster Shots for Other Fully Vaccinated People

COVID-19 booster shots are now authorized for all individuals in the U.S. who are 5 years and older.

On November 19, the FDA amended its emergency use authorization (EUA) for both the Pfizer and Moderna COVID-19 vaccines, authorizing the use of a single booster dose for all persons 18 years and older who completed the primary series.

The FDA later authorized a Pfizer booster shot for those aged 12 and older who completed the initial Pfizer vaccination series at least five months prior. Eligibility was then expanded to include those 5 years and older.

The agency had previously authorized a booster for all adults who received one shot of the Johnson & Johnson vaccine and for specific groups of people at increased risk for COVID-19 exposure or severe illness.

According to the CDC, eligible individuals are able to choose any authorized COVID-19 booster. However, it is now recommended that individuals get the Pfizer or Moderna mRNA COVID-19 vaccine over the Johnson & Johnson vaccine, following concerns about blood-clotting side effects. The Johnson & Johnson shot still remains an option for those who are not able or willing to get a different vaccine. 

Children and adolescents ages 5 to 17 who completed Pfizer's primary series are only eligible for the Pfizer booster.

On March 29, the FDA authorized additional mRNA booster doses for certain higher-risk individuals. All adults 50 and over who have received an initial mRNA booster dose at least four months prior are now eligible for a second booster dose.

The Pfizer and Johnson & Johnson booster shots will be administered with the same dosage as the initial vaccine, whereas Moderna’s will be a half dose (50 micrograms).

What This Means For You

According to the CDC, you are eligible for a COVID-19 booster shot if you are 5 years and older and:

  • Completed the Pfizer or Moderna primary vaccine series at least five months ago
  • Received the Johnson & Johnson vaccine at least two months ago

Persons age 50 and older who received a booster shot at least four months prior are now eligible for a second booster dose.

If you’re immunocompromised, talk to your doctor about getting an additional dose now. Experts recommend checking in with your state’s health department to get the latest information on where and when boosters will become available.

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.

12 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 Pfizer-BioNTech COVID-19 vaccine booster dose to children 5 through 11 years.

  2. Centers for Disease Control and Prevention. COVID-19 vaccine boosters.

  3. Centers for Disease Control and Prevention. COVID-19 vaccines for moderately or severely immunocompromised people.

  4. Centers for Disease Control and Prevention. CDC recommends additional boosters for certain individuals.

  5. Food and Drug Administration. Coronavirus (COVID-19) update: FDA authorizes additional vaccine dose for certain immunocompromised individuals.

  6. Food and Drug Administration. Coronavirus (COVID-19) update: FDA takes multiple actions to expand use of Pfizer-BioNTech COVID-19 vaccine.

  7. Centers for Disease Control and Prevention. Interim clinical considerations for use of COVID-19 vaccines currently approved or authorized in the United States.

  8. Oliver S. Data and clinical considerations for additional doses in immunocompromised people. Presented at Advisory Committee on Immunization. Atlanta, GA.

  9. Food and Drug Administration. Coronavirus (COVID-19) update: FDA expands eligibility for COVID-19 vaccine boosters.

  10. Food and Drug Administration. Coronavirus (COVID-19) update: FDA takes additional actions on the use of a booster dose for COVID-19 vaccines.

  11. Centers for Disease Control and Prevention. CDC endorses ACIP’s updated COVID-19 vaccine recommendations.

  12. Food and Drug Administration. Coronavirus (COVID-19) update: FDA authorizes second booster dose of two COVID-19 vaccines for older and immunocompromised individuals.

By Jennifer Chesak
Jennifer Chesak is a medical journalist, editor, and fact-checker with bylines in several national publications. She earned her Master of Science in journalism from Northwestern University's Medill School. Her coverage focuses on COVID-19, chronic health issues, women’s medical rights, and the scientific evidence around health and wellness trends.