An additional primary shot of a COVID-19 vaccine is recommended for people who are vaccinated and might not have had a strong enough immune response. In contrast, a booster dose is recommended for people who are vaccinated and whose immune response weakened over time. If you have a weakened immune system, please talk with your doctor about whether you should get an additional primary shot.
The CDC recommends that moderately to severely immunocompromised individuals who received the two-dose series of either Pfizer or Moderna get a third dose of the vaccine.
Who qualifies for an additional (third) primary series dose:
- To be considered fully vaccinated, ALL children ages 6 months – 4 years who received the Pediatric Pfizer vaccinations should get a third primary shot given at least 8 weeks after the 2nd dose
- People ages 5+ who completed the Pfizer primary series and are immunocompromised should get an additional primary shot of Pfizer 28 days after their 2nd dose
- People 6+ who completed the Moderna primary series and are immunocompromised should get an additional primary shot of Moderna 28 days after their 2nd dose
- Children ages 6 months – 5 years who completed the Moderna primary series and are immunocompromised should get an additional primary shot of Moderna 28 days after their 2nd dose
Studies have found that some immunocompromised people don’t always build the same level of immunity after vaccination the way non-immunocompromised people do and may benefit from an additional dose to ensure adequate protection against COVID-19.
Moderately to severely immunocompromised people who should receive an additional dose include:
- Receive active cancer treatment for tumors or cancers of the blood
- Received an organ transplant and are taking medicine to suppress the immune system
- Received a stem cell transplant within the last 2 years or are taking medicine to suppress the immune system
- Have moderate or severe primary immunodeficiency (such as DiGeorge syndrome, Wiskott-Aldrich syndrome)
- Have advanced or untreated HIV infection
- Receive active treatment with high-dose corticosteroids or other drugs that suppress immune response
Talk to your doctor to see if getting an additional dose is right for you. 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 recommendations listed above).
More information is available from the CDC: COVID-19 Vaccines for Moderately to Severely Immunocompromised People.
View this webpage for information about COVID-19 Boosters: Stay Up to Date with COVID-19 Vaccines Including Boosters | CDC