About Boosters and Third Doses

"Booster Shot" vs. "Second/Third Dose": What's the Difference?

  • A booster shot is for individuals whose immune response to COVID-19 might have weakened over time.
  • A second (J&J) or third (Pfizer/Moderna) dose, alternately called an additional dose, is for individuals who might not have built a strong enough level of immunity from their primary vaccine series due to being moderately to severely immunocompromised.

Who Is Eligible?

Please note that the eligibility information below reflects CDC guidelines as of 4/8/2022.

Booster Shot Eligibility

Vaccine Manufacturer When to Get It Who Is Eligible
Pfizer-BioNTech At least five (5) months after receiving the second dose of the initial two-dose vaccine series.
  • Everyone 12 years and older
Moderna At least five (5) months after receiving the second dose of the initial two-dose vaccine series.
  • Adults 18 years and older
Johnson & Johnson At least two (2) months after receiving the initial, single-dose Johnson & Johnson vaccine.
  • Adults 18 years and older

 (Source)

Second Booster Shot Eligibility

Note: The second booster must be an mRNA COVID-19 vaccine (Pfizer-BioNTech or Moderna).

Vaccine Manufacturer When to Get It Who Is Eligible
Pfizer-BioNTech At least four (4) months after receiving your first booster.
  • Adults 50 years and older
Moderna At least four (4) months after receiving your first booster.
  • Adults 50 years and older
Johnson & Johnson At least four (4) months after receiving your first booster.
  • Anyone who received a J&J vaccine for both their primary dose and first booster
  • Adults 50 years and older who received a J&J vaccine for their primary dose, regardless of what type of first booster was received

 (Source)

Second/Third Dose Eligibility and Booster Timing

Who is Eligible

  • Individuals who are moderately to severely immunocompromised, which includes those who have:
    • Been receiving 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
    • Moderate or severe primary immunodeficiency (such as DiGeorge syndrome, Wiskott-Aldrich syndrome)
    • Advanced or untreated HIV infection
    • Active treatment with high-dose corticosteroids or other drugs that may suppress your immune response
Vaccine Manufacturer Age Group

Primary Series

(Immunocompromised Individuals)

Booster Timing

(Immunocompromised Individuals)

Pfizer-BioNTech  5-11 years

3 doses:

  • 2nd dose given 3 weeks (21 days) after 1st dose
  • 3rd dose given at least 4 weeks (28 days) after second dose
Not recommended at this time.
12+ years

3 doses:

  • 2nd dose given 3 weeks (21 days) after 1st dose
  • 3rd dose given at least 4 weeks (28 days) after 2nd dose
  • Booster: Given at least 3 months after 3rd dose
  • Second* booster: Given at least 4 months after 1st booster
Moderna 18+ years

3 doses:

  • 2nd dose given 4 weeks (28 days) after 1st dose
  • 3rd dose given at least 4 weeks (28 days) after second dose
  • Booster: Given at least 3 months after 3rd dose
  • Second* booster: Given at least 4 months after first booster
Johnson & Johnson 18+ years

2 doses:

  • 1st dose: J&J/Janssen
  • 2nd dose: either Pfizer-BioNTech or Moderna given at least 4 weeks (28 days) after first dose
  • Booster: Given at least 2 months after 2nd dose
  • Second* booster: Given at least 4 months after first booster

The Pfizer-BioNTech COVID-19 vaccine is the only vaccine currently approved for individuals ages 5+, therefore only the Pfizer-BioNTech vaccine may be used for additional doses and boosters.

*At this time, one booster is needed to be considered "up-to-date" on COVID-19 vaccination per CDC guidelines. However, immunocompromised individuals may choose to receive a second booster once the recommended time from their first booster has elapsed.

 ( Source)