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. 2023 Jan 13;76(2):252-262.
doi: 10.1093/cid/ciac785.

Effectiveness of Messenger RNA-1273 Vaccine Booster Against Coronavirus Disease 2019 in Immunocompetent Adults

Ana Florea  1 , Lina S Sy  1 , Lei Qian  1 , Bradley K Ackerson  1 , Yi Luo  1 , Julia E Tubert  1 , Gina S Lee  1 , Jennifer H Ku  1 , Katia J Bruxvoort  1   2 , Carla A Talarico  3 , Sijia Qiu  1 , Yun Tian  1 , Hung Fu Tseng  1   4
Affiliations
Free PMC article

Effectiveness of Messenger RNA-1273 Vaccine Booster Against Coronavirus Disease 2019 in Immunocompetent Adults

Ana Florea et al. Clin Infect Dis. .
Free PMC article

Abstract

Background: We conducted a prospective cohort study at Kaiser Permanente Southern California to evaluate the relative vaccine effectiveness (rVE) of a booster dose vs 2-dose primary series of messenger RNA (mRNA)-1273 in immunocompetent individuals.

Methods: Immunocompetent adults who received a booster dose of mRNA-1273 from October 2021 through December 2021 were matched 1:1 to randomly selected 2-dose mRNA-1273 recipients by age, sex, race/ethnicity, and second-dose date and followed up through January 2022. Cox proportional hazards models were used to estimate adjusted hazard ratios (aHRs) with 95% confidence intervals (CIs), comparing outcomes (severe acute respiratory syndrome coronavirus 2 [SARS-CoV-2] infection and coronavirus disease 2019 [COVID-19] hospitalization and hospital death) in the booster-dose and 2-dose groups. Adjusted rVE (%) was calculated as (1 - aHR) × 100. aHRs and rVE were also estimated by subgroup and month of follow-up.

Results: The study included 431 328 booster-dose vaccinated adults matched to 431 328 2-dose vaccinated adults. rVE was 61.3% (95% CI: 60.5%-62.2%) against SARS-CoV-2 infection, 89.0% (86.2%-91.2%) against COVID-19 hospitalization, and 96.0% (68.0%-99.5%) against COVID-19 hospital death. rVE against SARS-CoV-2 infection ranged from 55.6% to 66.7% across all subgroups. rVE against SARS-CoV-2 infection decreased from 67.1% (0 to <1 month of follow-up) to 30.5% (2 to <3 months). For COVID-19 hospitalization, rVE decreased from 91.2% (0 to <1 month) to 78.7% (2 to <3 months).

Conclusions: Among immunocompetent adults, the mRNA-1273 booster conferred additional protection against SARS-CoV-2 infection and severe COVID-19 disease compared with the 2-dose mRNA-1273 primary series during periods of Delta and Omicron predominance.

Keywords: COVID-19; booster; immunocompetent; mRNA-1273; vaccine effectiveness.

Conflict of interest statement

Potential conflicts of interest . A. F., L. S. S., L. Q., B. K. A., Y. L., J. E. T., G. S. L., J. H. K., S. Q., and H. F. T. are employees of Kaiser Permanente Southern California, which has been contracted by Moderna, Inc, to conduct this study. K. J. B. is an adjunct investigator at Kaiser Permanente Southern California. Y. T. was an employee of Kaiser Permanente Southern California at the time of these analyses and is currently an employee of Pharmaceutical Product Development Inc. C. A. T. was an employee of and a shareholder in Moderna, Inc, at the time of these analyses and is currently an employee of AstraZeneca. A. F. received funding from Pfizer, GSK, and Gilead unrelated to this work. L. S. S. received funding from GSK, Dynavax, and Seqirus unrelated to this work. L. Q. received funding from GSK and Dynavax unrelated to this work. B. K. A. received funding from GSK, Dynavax, Seqirus, Genentech, Moderna, and Pfizer unrelated to this work. Y. L. received funding from GSK, Seqirus, and Pfizer unrelated to this work. J. E. T. received funding from Pfizer unrelated to this work. G. S. L. received funding from GSK unrelated to this work. J. H. K. received funding from GSK unrelated to this work. K. J. B. received funding from GSK, Dynavax, Pfizer, Gilead, and Seqirus unrelated to this work. S. Q. received funding from Dynavax unrelated to this work. Y. T. received funding from GSK unrelated to this work. H. F. T. received funding from GSK and Seqirus unrelated to this and served on advisory boards for Janssen and Pfizer. All authors have submitted the ICMJE Form for Disclosure of Potential Conflicts of Interest. Conflicts that the editors consider relevant to the content of the manuscript have been disclosed.

Figures

Graphical abstract
Graphical abstract
Figure 1.
Figure 1.
Flowchart for booster-dose and 2-dose messenger RNA-1273 vaccine cohorts. Abbreviations: COVID-19, coronavirus disease 2019; KPSC, Kaiser Permanente Southern California; mRNA, messenger RNA.
Figure 2.
Figure 2.
Cumulative incidence estimates of SARS-CoV-2 infection, COVID-19 hospitalization, and COVID-19 hospital death in booster-dose and 2-dose messenger RNA-1273 immunocompetent vaccine cohorts. A, SARS-CoV-2 infection. B, COVID-19 hospitalization. C, COVID-19 hospital death. Abbreviations: COVID-19, coronavirus disease 2019; SARS-CoV-2, severe acute respiratory syndrome coronavirus 2.
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