Effectiveness of a bivalent mRNA vaccine dose against symptomatic SARS-CoV-2 infection among U.S. Healthcare personnel, September 2022–May 2023

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https://www.sciencedirect.com/science/article/pii/S0264410X23012872

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https://doi.org/10.1016/j.vaccine.2023.10.072
 http://hdl.handle.net/11603/34547

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UMBC Faculty Collection
UMBC Emergency and Distaster Health Systems

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https://orcid.org/0000-0003-0092-1750

Date

2024-04-11

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journal articles
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Program

Citation of Original Publication

Plumb, Ian D., Melissa Briggs Hagen, Ryan Wiegand, Ghinwa Dumyati, Christopher Myers, Karisa K. Harland, Anusha Krishnadasan, et al. “Effectiveness of a Bivalent MRNA Vaccine Dose against Symptomatic SARS-CoV-2 Infection among U.S. Healthcare Personnel, September 2022–May 2023.” Vaccine 42, no. 10 (April 11, 2024): 2543–52. https://doi.org/10.1016/j.vaccine.2023.10.072.

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This work was written as part of one of the author's official duties as an Employee of the United States Government and is therefore a work of the United States Government. In accordance with 17 U.S.C. 105, no copyright protection is available for such works under U.S. Law.
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Subjects

Bivalent
COVID-19
COVID-19 vaccines
Healthcare personnel
mRNA vaccines
SARS-CoV-2
Vaccine effectiveness

Abstract

Background: Bivalent mRNA vaccines were recommended since September 2022. However, coverage with a recent vaccine dose has been limited, and there are few robust estimates of bivalent VE against symptomatic SARS-CoV-2 infection (COVID-19). We estimated VE of a bivalent mRNA vaccine dose against COVID-19 among eligible U.S. healthcare personnel who had previously received monovalent mRNA vaccine doses. Methods: We conducted a case-control study in 22 U.S. states, and enrolled healthcare personnel with COVID-19 (case-participants) or without COVID-19 (control-participants) during September 2022–May 2023. Participants were considered eligible for a bivalent mRNA dose if they had received 2–4 monovalent (ancestral-strain) mRNA vaccine doses, and were >=67 days after the most recent vaccine dose. We estimated VE of a bivalent mRNA dose using conditional logistic regression, accounting for matching by region and four-week calendar period. We adjusted estimates for age group, sex, race and ethnicity, educational level, underlying health conditions, community COVID-19 exposure, prior SARS-CoV-2 infection, and days since the last monovalent mRNA dose. Results: Among 3,647 healthcare personnel, 1,528 were included as case-participants and 2,119 as control-participants. Participants received their last monovalent mRNA dose a median of 404 days previously; 1,234 (33.8%) also received a bivalent mRNA dose a median of 93 days previously. Overall, VE of a bivalent dose was 34.1% (95% CI, 22.6%–43.9%) against COVID-19 and was similar by product, days since last monovalent dose, number of prior doses, age group, and presence of underlying health conditions. However, VE declined from 54.8% (95% CI, 40.7%–65.6%) after 7–59 days to 21.6% (95% CI 5.6%–34.9%) after >=60 days. Conclusions: Bivalent mRNA COVID-19 vaccines initially conferred approximately 55% protection against COVID-19 among U.S. healthcare personnel. However, protection waned after two months. These findings indicate moderate initial protection against symptomatic SARS-CoV-2 infection by remaining up-to-date with COVID-19 vaccines.