Top 5 Takeaways

  1. Reduced Reactions Post-Booster: Immunocompromised individuals aged ≥12 years reported fewer local and systemic reactions after the fourth dose (mRNA booster) compared to after the third dose of the primary series.
  2. Rarity of Serious Adverse Events: Among this population, only 17 serious adverse events were reported to the Vaccine Adverse Event Reporting System (VAERS), highlighting the rarity of severe reactions following booster vaccination.
  3. Booster Recommendations: The Advisory Committee on Immunization Practices (ACIP) advises that immunocompromised persons aged ≥12 should receive a first booster ≥3 months after the 3-dose primary COVID-19 vaccination series and a second booster ≥4 months after the first.
  4. Safety Profile Consistency: Safety findings after the mRNA booster dose were consistent with previous observations in nonimmunocompromised individuals, indicating a generally safe profile for the booster among those with presumed immunocompromise.
  5. Health Impact and Recovery: A minority reported that vaccine reactions impacted their ability to perform daily activities or attend work/school, but these reports were less frequent after the booster dose compared to after the third primary series dose.

Original Article Author and Citation

Corresponding Author

Anne M. Hause,

Suggested Citation

Hause AM, Baggs J, Marquez P, et al. Safety Monitoring of COVID-19 mRNA Vaccine First Booster Doses Among Persons Aged ≥12 Years with Presumed Immunocompromise Status — United States, January 12, 2022–March 28, 2022. MMWR Morb Mortal Wkly Rep 2022;71:899–903. DOI:


The report outlines the CDC’s findings on the safety of first booster doses of mRNA COVID-19 vaccines among presumed immunocompromised persons aged ≥12 years. It utilizes data from v-safe and VAERS to assess adverse events and reactions following the administration of a fourth vaccine dose during January 12, 2022–March 28, 2022. Approximately 518,113 persons received a fourth dose during this period.


This study reviewed adverse events reported to v-safe, a voluntary smartphone-based safety surveillance system, and VAERS, a passive surveillance system for vaccine-associated adverse events. The focus was on reports following a fourth mRNA COVID-19 vaccine dose, presumed to be administered as a booster to immunocompromised individuals.


The observed safety profile for the mRNA COVID-19 vaccine booster among presumed immunocompromised individuals was consistent with safety data from nonimmunocompromised populations. The less frequent reporting of adverse reactions after the booster dose, compared to the third primary series dose, supports the safety of booster administration in this group.


The report concludes that booster doses are associated with a low incidence of serious adverse events among immunocompromised individuals aged ≥12 years. It emphasizes the importance of continuing vaccination efforts in this population, following ACIP’s recommendations for booster administration.

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