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. 2022 Dec 19;75(12):2161-2168.
doi: 10.1093/cid/ciac328.

Relative Vaccine Effectiveness of a Severe Acute Respiratory Syndrome Coronavirus 2 Messenger RNA Vaccine Booster Dose Against the Omicron Variant

Adeel A Butt  1   2   3 , Victor B Talisa  1   4 , Obaid S Shaikh  1   5 , Saad B Omer  6 , Florian B Mayr  1   4
Affiliations

Relative Vaccine Effectiveness of a Severe Acute Respiratory Syndrome Coronavirus 2 Messenger RNA Vaccine Booster Dose Against the Omicron Variant

Adeel A Butt et al. Clin Infect Dis. .

Abstract

Background: The current severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) vaccines may be less effective against the Omicron variant than against earlier variants. With recent resurgence of SARS-CoV-2 cases, the role of booster doses of the vaccine needs to be highlighted.

Methods: Using a retrospective cohort study design emulating a target trial, we determined the relative vaccine effectiveness (RVE) of a homologous booster dose of a SARS-CoV-2 messenger RNA (mRNA) vaccine compared with the primary vaccine series alone in preventing infection, hospitalization, and intensive care unit admission, and death in the Department of Veterans Affairs healthcare system in the United States. Among infection-free survivors who received 2 doses of a mRNA vaccine before 30 April 2021, we identified those who received a booster between 22 September and 25 December 2021 and matched them 1:1 with individuals who did not receive a booster.

Results: Among 2 384 272 previously uninfected persons with 2 doses of an mRNA vaccine by 30 April 2021, we identified 462 950 booster recipients between 22 September and 25 December 2021, who were matched 1:1 with non-booster recipients. The RVE (95% confidence interval) was 19% (17%-22%) for confirmed infection, 52% (46%-57%) for hospitalization, and 83% (65%-92%) for intensive care unit admission or death. Recipients of the mRNA-1273 vaccine had a lower cumulative incidence of infections and hospitalizations than recipients of the BNT162b2 vaccine (log-rank P <.001 for both comparisons).

Conclusions: While the RVE of SARS-CoV-2 mRNA booster vaccine dose in preventing infection against the Omicron variant is low, it is substantial in preventing hospitalization and high in preventing the most severe/critical disease.

Keywords: Delta variant; Omicron variant; SARS-CoV-2; booster; vaccine effectiveness.

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Conflict of interest statement

Potential conflicts of interest. A. A. B. has received investigator-initiated grant funding from Gilead Sciences (to the institution, Veterans Health Foundation of Pittsburgh), unrelated to the work presented here. F. B. M. is supported by a grant from the National Institutes of Health (career development award K23GM132688), related to this work. All other authors report no potential conflicts. 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

Figure 1.
Figure 1.
Selection of cohorts used to study the effectiveness of BNT162b2 and mRNA-1273 booster vaccination against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Exclusion criteria were not mutually exclusive. The primary and secondary analyses estimated the effectiveness of 3 versus 2 doses of the same messenger RNA (mRNA) vaccine during the periods of Omicron variant predominance (Omicron >92% prevalent) (primary analysis) or Delta variant predominance (Delta >92% prevalent) (secondary analysis). When patients or controls were excluded, both in the matched pair were excluded.
Figure 2.
Figure 2.
Cumulative incidence of documented infections (left panels) and hospitalizations (right panels) in the BNT-162b2 and mRNA-1273 booster-dose groups and matched controls during the period of Omicron variant predominance. The upper panels compare the cumulative incidence of documented infections and hospitalization among recipients of 2 vs. 3 doses of the BNT-162b2 vaccine. The lower panels compare the cumulative incidence of documented infections and hospitalization among recipients of 2 vs. 3 doses of the mRNA-1273 vaccine.
Figure 3.
Figure 3.
Cumulative incidence of documented infections (left panel) and hospitalizations (right panel) among recipients of the BNT-162b2 and mRNA-1273 vaccines during the period of Omicron variant predominance among those who had received a booster dose.
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References

    1. Butt AA, Omer SB, Yan P, Shaikh OS, Mayr FB. SARS-CoV-2 vaccine effectiveness in a high-risk national population in a real-world setting. Ann Intern Med 2021; 174:1404–8. - PMC - PubMed
    1. Abu-Raddad LJ, Chemaitelly H, Butt AA; National Study Group for COVID-19 Vaccination . Effectiveness of the BNT162b2 Covid-19 vaccine against the B.1.1.7 and B.1.351 variants. N Engl J Med 2021; 385:187–9. - PMC - PubMed
    1. Chemaitelly H, Yassine HM, Benslimane FM, et al. mRNA-1273 COVID-19 vaccine effectiveness against the B.1.1.7 and B.1.351 variants and severe COVID-19 disease in Qatar. Nat Med 2021; 27:1614–21. - PubMed
    1. Dagan N, Barda N, Kepten E, et al. BNT162b2 mRNA Covid-19 vaccine in a nationwide mass vaccination setting. N Engl J Med 2021; 384:1412–23. - PMC - PubMed
    1. Goldberg Y, Mandel M, Bar-On YM, et al. Waning immunity after the BNT162b2 vaccine in Israel. N Engl J Med 2021; 385:e85. - PMC - PubMed

Supplementary concepts