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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

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

Ana Florea et al. Clin Infect Dis. .

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.

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Figures

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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.
See this image and copyright information in PMC

References

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