Effectiveness of mRNA-BNT162b2, mRNA-1273, and ChAdOx1 nCoV-19 vaccines against COVID-19 in healthcare workers: an observational study using surveillance data. (November 2021)

• Record Type: Journal Article
• Authors: Paris, Christophe; Perrin, Sophie; Hamonic, Stephanie; Bourget, Baptiste; Roué, Clémence; Brassard, Olivier; Tadié, Emilie; Gicquel, Vincent; Bénézit, François; Thibault, Vincent; Garlantézec, Ronan; Tattevin, Pierre
• Is Part Of: Clinical microbiology and infection. Volume 27:Number 11(2021)
• Page Start: 1699.e5
• Page End: 1699.e8
• Publication Date: 2021-11
• Subjects: ChAdOx1 nCoV-19 -- COVID-19 -- Effectiveness -- Healthcare workers -- mRNA-1273 -- mRNABNT162b2 -- Vaccine; Medical microbiology -- Periodicals; Diagnostic microbiology -- Periodicals; Communicable diseases -- Periodicals; Infection -- Periodicals; 616.01
• DOI: 10.1016/j.cmi.2021.06.043
• Languages: English
• ISSNs: 1198-743X

Abstract

Abstract: Objectives: Healthcare workers (HCWs) at increased risk of coronavirus disease 2019 (COVID-19) were among the primary targets for vaccine campaigns. We aimed to estimate the protective efficacy of the first three COVID-19 vaccines available in Western Europe. Methods: We merged two prospective databases that systematically recorded, in our institution: (a) HCWs positive for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) by RT-PCR on nasopharyngeal samples, and (b) HCWs who received at least one dose of COVID-19 vaccine. We excluded HCWs with SARS-CoV-2 infection during the 6 months prior to the study. HCWs were categorized as non-vaccinated if they received no vaccine and until the first injection +13 days, partially vaccinated from the first injection +14 days to the second injection +13 days, and fully vaccinated thereafter. Results: Of the 8165 HCWs employed in our institution, 360 (4.4%) tested positive for SARS-CoV-2 by RT-PCR during the study period (4th January to 17th May 2021). Incidence was 9.1% (8.2–10.0) in non-vaccinated HCWs, 1.2% (0.7–1.9) after one dose of ChAdOx1 nCoV-19, 1.4% (0.6–2.3) and 0.5% (0.1–1.0) after one and two doses of mRNA BNT162b2, 0.7% (0.1–1.9) and 0% after one and two doses of mRNA-1273 (p < 0.0001). Vaccine effectiveness (Cox model) was estimated at, respectively, 86.2% (76.5–91.0), 38.2% (6.3–59.2), and 49.2% (19.1–68.1) 14 days after the first dose for ChAdOx1 nCoV-19, mRNA-1273, and mRNA-BNT162b2, and 100% (ND) and 94.6% (61.0–99.2) 14 days after the second dose for mRNA-1273 and mRNA-BNT162b2. Conclusions: In this real-world study, the observed effectiveness of COVID-19 vaccines in HCWs was in line with the efficacy reported in pivotal randomized trials.