Top 5 Takeaways

  1. Vaccine Effectiveness (VE): Among immunocompromised adults, the VE of 2-dose monovalent mRNA COVID-19 vaccines against hospitalization during Omicron predominance was 36%. VE increased to 67% after a third dose but declined to 32% ≥90 days after dose 3 and 43% after a fourth dose during BA.2/BA.2.12.1 and BA.4/BA.5 predominance.
  2. ACIP Recommendations: The Advisory Committee on Immunization Practices (ACIP) recommended a 3-dose primary series and a fourth booster dose for adults with immunocompromising conditions, following with a bivalent booster targeting BA.4 and BA.5 sublineages.
  3. Omicron Sublineage Variability: Protection was moderate even after a 3-dose primary series or booster, with a noted decline in VE during BA.2/BA.2.12.1 and BA.4/BA.5 periods compared to BA.1.
  4. Additional Protective Measures: Updated bivalent vaccine boosters targeting Omicron sublineages and other measures like prophylactic antibody therapy, antivirals, and nonpharmaceutical interventions are suggested for persons with immunocompromising conditions.
  5. Study Limitations: Factors like a range of immune suppression associated with each condition and the lack of individual SARS-CoV-2 genomic sequencing data pose limitations to the study.

Original Article Author and Citation

Corresponding Author

Amadea Britton,

Suggested Citation

Britton A, Embi PJ, Levy ME, et al. Effectiveness of COVID-19 mRNA Vaccines Against COVID-19–Associated Hospitalizations Among Immunocompromised Adults During SARS-CoV-2 Omicron Predominance — VISION Network, 10 States, December 2021—August 2022. MMWR Morb Mortal Wkly Rep 2022;71:1335–1342. DOI:


This study evaluated the VE of monovalent mRNA COVID-19 vaccines among immunocompromised adults during the predominance of the Omicron variant. It revealed a moderate VE after a 3-dose primary series or booster dose. However, there was a notable decline in VE during BA.2/BA.2.12.1 and BA.4/BA.5 periods compared to the BA.1 period.


The study employed a test-negative design, assessing VE among hospitalized adults with immunocompromising conditions and COVID-19–like illness. Immunocompromising conditions were identified from electronic medical records, and vaccination status was obtained from health records or immunization registries.


The study discusses the lower VE among immunocompromised individuals compared to immunocompetent persons during Omicron predominance. It emphasizes the importance of the updated bivalent booster vaccines and additional protective measures for this population.


The study concludes that monovalent vaccination remains moderately protective in persons with immunocompromising conditions. However, the protection is not complete, especially during recent Omicron sublineage predominance periods. Therefore, the use of updated bivalent boosters and other protective measures is recommended.


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