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.
Keywords: COVID-19; ChAdOx1 nCoV-19; Effectiveness; Healthcare workers; Vaccine; mRNA-1273; mRNABNT162b2.
【저자키워드】 COVID-19, Vaccine, Healthcare workers, mRNA-1273, Effectiveness, ChAdOx1 nCoV-19, mRNABNT162b2., 【초록키워드】 coronavirus disease, SARS-CoV-2, Efficacy, coronavirus, Europe, COVID-19 vaccine, SARS-COV-2 infection, RT-PCR, database, healthcare worker, HCWs, target, ChAdOx1, mRNA BNT162b2, Protective, dose, HCW, randomized trials, acute respiratory syndrome, increased risk, second dose, first dose, study period, Nasopharyngeal samples, injection, positive, Cox model, tested, reported, excluded, recorded, 【제목키워드】 healthcare, ChAdOx1 nCoV-19 vaccine, surveillance data,