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Effectiveness of two coronavirus disease 2019 (COVID-19) vaccines (viral vector and inactivated viral vaccine) against severe acute respiratory coronavirus virus 2 (SARS-CoV-2) infection in a cohort of healthcare workers
Journal article   Open access   Peer reviewed

Effectiveness of two coronavirus disease 2019 (COVID-19) vaccines (viral vector and inactivated viral vaccine) against severe acute respiratory coronavirus virus 2 (SARS-CoV-2) infection in a cohort of healthcare workers

Alexandre R. Marra, Joao Luiz Miraglia, Daniel Tavares Malheiros, Yang Guozhang, Vanessa Damazio Teich, Elivane da Silva Victor, Joao Renato Rebello Pinho, Adriana Cypriano, Laura Wanderly Vieira, Miria Polonio, …
Infection control and hospital epidemiology, Vol.44(1), pp.75-81
01/2023
DOI: 10.1017/ice.2022.50
PMCID: PMC9002147
PMID: 35351217
Appears in  UI Libraries Support Open Access
url
https://doi.org/10.1017/ice.2022.50View
Published (Version of record) Open Access

Abstract

Objective: We investigated real-world vaccine effectiveness for Oxford-AstraZeneca (ChAdOx1) and CoronaVac against laboratory-confirmed severe acute respiratory coronavirus virus 2 (SARS-CoV-2) infection among healthcare workers (HCWs). Methods: We conducted a retrospective cohort study among HCWs (aged >= 18 years) working in a private healthcare system in Brazil between January 1, 2021 and August 3, 2021, to assess vaccine effectiveness. We calculated vaccine effectiveness as 1 - rate ratio (RR), with RR determined by adjusting Poisson models with the occurrence of SARS-CoV-2 infection as the outcome and the vaccination status as the main variable. We used the logarithmic link function and simple models adjusting for sex, age, and job types. Results: In total, 13,813 HCWs met the inclusion criteria for this analysis. Among them, 6,385 (46.2%) received the CoronaVac vaccine, 5,916 (42.8%) received the ChAdOx1 vaccine, and 1,512 (11.0%) were not vaccinated. Overall, COVID-19 occurred in 6% of unvaccinated HCWs, 3% of HCWs who received 2 doses of CoronaVac vaccine, and 0.7% of HCWs who received 2 doses of ChAdOx1 vaccine (P < .001). In the adjusted analyses, the estimated vaccine effectiveness rates were 51.3% for CoronaVac, and 88.1% for ChAdOx1 vaccine. Both vaccines reduced the number of hospitalizations, the length of hospital stay, and the need for mechanical ventilation. In addition, 19 SARS-CoV-2 samples from 19 HCWs were screened for mutations of interest. Of 19 samples, 18 were the gamma (gamma) variant. Conclusions: Although both COVID-19 vaccines (viral vector and inactivated virus) can significantly prevent COVID-19 among HCWs, CoronaVac was much less effective. The COVID-19 vaccines were also effective against the dominant gamma variant.
 Infectious Diseases Life Sciences & Biomedicine Public, Environmental & Occupational Health Science & Technology UIOWA OA Agreement

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