Introduction: We aimed to evaluate the prevalence and clinical outcomes of COVID-19 in healthcare workers (HCWs) in the pre-vaccination and post-vaccination periods. In addition, we determined factors associated with the development of COVID-19 after vaccination.
Methodology: In this analytical cross-sectional epidemiological study, HCWs who were vaccinated between January 14, 2021, and March 21, 2021, were included. HCWs were followed up for 105 days after the 2 doses of CoronaVac. Pre-vaccination and post-vaccination periods were compared.
Results: A total of 1,000 HCWs were included, 576 patients (57.6%) were male, and the mean age was 33.2 ± 9.6 years. In the last 3 months during the pre-vaccination period, 187 patients had COVID-19, and the cumulative incidence of COVID-19 was 18.7%. Six of these patients were hospitalized. Severe disease was observed in three patients. In the first 3 months post-vaccination period, COVID-19 was detected in 50 patients, and the cumulative incidence of the disease was determined to be 6.1%. Hospitalization and severe disease were not detected. Age (p = 0.29), sex (OR = 1.5, p = 0.16), smoking (OR = 1.29, p = 0.43), and underlying diseases (OR = 1.6, p = 0.26) were not associated with post-vaccination COVID-19. A history of COVID-19 significantly reduced the likelihood of the development of post-vaccination COVID-19 in multivariate analysis (p = 0.002, OR = 0.16, 95% CI = 0.05-0.51).
Conclusions: CoronaVac significantly reduces the risk of SARS-CoV-2 infection and alleviates the severity of COVID-19 in the early period. Additionally, HCWs who have been infected and vaccinated with CoronaVac are less likely to be reinfected with COVID-19.
Keywords: COVID-19; CoronaVac; healthcare workers.
Copyright (c) 2023 Yusuf Emre Ozdemir, Aysegul Inci Sezen, Serkan Surme, Sevtap Senoglu, Zuhal Yesilbag, Meryem Sahin Ozdemir, Osman Faruk Bayramlar, Emine Ilay Duman, Nomin Bold, Habip Gedik, Kadriye Kart Yasar.