Effectiveness of CoronaVac vaccination against COVID-19 development in healthcare workers: real-life data.

ABSTRACT

Background: This study was designed to investigate the effectiveness of CoronaVac in preventing COVID-19 in healthcare workers (HCWs) during the Alpha variant-dominant period. Materials & methods: Follow-up was initiated 14 days after the second dose for double-dose vaccinated HCWs and on 25 February 2021, for the unvaccinated group. The incidence rate ratio was calculated to estimate the unadjusted effectiveness. Cox regression was used to adjust the effectiveness of CoronaVac. Results & Conclusion: The adjusted effectiveness of CoronaVac against COVID-19 was 65% (95% CI 50-75%). Compared with the results of the phase III trial conducted in Turkey, a lower effectiveness of CoronaVac against COVID-19 was detected in this real-life study. This finding suggests that mass vaccination and booster doses are needed.

This study was designed to investigate the effectiveness of CoronaVac in preventing COVID-19 in healthcare workers (HCWs) during the alpha variant-dominant period. A total of 1911 HCWs were included. While COVID-19 developed in 4.1% of double-dose vaccinated HCWs and 11.27% of unvaccinated HCWs, the effectiveness of CoronaVac in preventing the development of COVID-19 was 65%. Compared with the results of a previous trial in Turkey, a lower effectiveness of CoronaVac against COVID-19 was detected in this real-life study. This finding suggests that mass vaccination and booster doses are needed.