Evaluation of COVID-19 Cases Detected Positive by RT-PCR

Objective: Immunization by vaccination has a crucial role in controlling COVID-19 pandemic. Determination of the factors affecting the effectiveness of the vaccine can increase the success rates. We aimed to investigate the effectiveness of CoronaVac and factors affecting its effectiveness in healthcare workers. Methods: This retrospective study included healthcare personnel (n=2666) working at a training and research hospital. Logistic regression analysis was used for analyzing the effects of all variables including vaccination status on the development of COVID-19. Adjusted odds ratios calculated by logistic regression analysis were used to determine the vaccine effectiveness. Stratified analyses wre performed for the determination of the interaction/effect modification regarding the vaccine effectiveness. Results: Mean age of the 2.666 healthcare workers included in this study was 37,3±10,2 and 55,8% (n=1488) were females and %44,2 (n=1178) were males. In this study gender and history of COVID-19 infection was found to be an effect modifier for the vaccine effectiveness by the stratified analysis. The effectiveness of the CoronaVac vaccine in preventing development of COVID-19 diagnosed by real-time polymerase chain reaction (RT-PCR) in healthcare workers was 84,5% (95%CI: 73,3-91) in women and 47% (95%CI: 1,7-71,4) in men. Being a medical doctor or a registered nurse, working in ICU or a COVID-19 clinic, a positive history of COVID-19 and COVID-19 vaccination were other protective factors against COVID-19 infection. Conclusion: Determination of the factors affecting the effectiveness of the vaccine can increase the success rates. Vaccination programs may need to be modified if there is a COVID-19 history or gender-related difference in vaccine effectiveness. © 2022,Turk Hijyen ve Deneysel Biyoloji Dergisi. All Rights Reserved.