Top 5 Takeaways

1. Second mRNA COVID-19 Booster’s Efficacy: In nursing home residents, a second mRNA COVID-19 booster was found to be 74% effective at 60 days against severe COVID-19 outcomes (including hospitalization or death) and 90% effective against death alone, compared to a single booster dose.
2. Study Population and Period: The study examined nursing home residents from 196 facilities across 19 states, focusing on the period between March 29 and July 25, 2022, during which Omicron subvariants were prevalent.
3. Vaccine Effectiveness (VE) Findings: The analysis showed a 60-day VE of 25.8% against SARS-CoV-2 infection, 73.9% against severe outcomes (hospitalization or death), and 89.6% against death alone, for those who received a second booster.
4. Study Design and Methodology: This emulated target trial compared effectiveness of a second booster dose versus non-receipt in residents who had received three previous doses. A total of 9,527 residents were included, with 3,245 receiving a second booster.
5. Public Health Implications: The findings underscore the importance of up-to-date COVID-19 vaccination, including bivalent vaccine booster doses, to prevent severe outcomes in nursing home residents.

Original Article Author and Citation

Corresponding Author

Kevin W. McConegh, kevin.mcconeghy@va.gov.

Suggested Citation

McConeghy KW, White EM, Blackman C, et al. Effectiveness of a Second COVID-19 Vaccine Booster Dose Against Infection, Hospitalization, or Death Among Nursing Home Residents — 19 States, March 29–July 25, 2022. MMWR Morb Mortal Wkly Rep 2022;71:1235–1238. DOI: http://dx.doi.org/10.15585/mmwr.mm7139a2.

Summary

This study investigated the effectiveness of a second mRNA COVID-19 booster dose in nursing home residents. Focused on a cohort from 196 U.S. nursing homes, the study assessed VE against SARS-CoV-2 and severe outcomes, including hospitalization and death.

Methods

The analysis emulated target trials comparing the effectiveness of a second mRNA booster against no receipt among recipients of two primary doses followed by one booster dose. Participants were nursing home residents from 196 facilities in 19 states, with a follow-up period through July 25, 2022. The study used propensity score matching and Kaplan-Meier estimators for VE assessment.

Discussion

The study found substantial effectiveness of the second booster dose against severe COVID-19 outcomes, particularly in the context of circulating Omicron subvariants. The results were in line with previous studies but noted limitations in the comparison due to varying methodologies and population health conditions.

Conclusion

The second mRNA COVID-19 booster dose provided significant additional protection against severe COVID-19 outcomes in nursing home residents, emphasizing the need for ongoing vaccination efforts in this vulnerable population.

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