Adverse Events Report of Inactivated COVID-19 Vaccine

Overview

Numerous vaccination studies are conducted to protect against COVID-19 infection, and preclinical and clinical studies are still ongoing worldwide. During this extraordinary period, the necessity to perform COVID-19 vaccine studies and immunization programs together has emerged. Many manufacturing companies have started mass production of vaccines accepting the risk of failure of vaccines during trials. Vaccine Adverse Effects (VAEs) need to be documented quickly. We aimed to determine the VAEs and to compare the frequency of VAEs between groups according to socio-demographic characteristics after the inactivated vaccine (Corona Vac®) was administered to healthcare workers (HCWs) in Turkey. In this study, an online questionnaire was delivered to volunteer healthcare workers across the whole country. Sociodemographic characteristics, medical history, history of COVID-19 infection, and VAEs occurring after the first and second doses of inactivated vaccine were evaluated.

A new coronavirus, severe acute respiratory syncytial coronavirus 2 (SARS-CoV-2) first appeared in China at the end of 2019 and attracted attention with clusters of pneumonia-like cases, which were later defined as coronavirus disease 2019 (COVID-19). Vaccine development is usually achieved over decades and therefore it is unprecedented to have access to such a large number of approved vaccines for COVID-19. In this process, great efforts were made by many organizations to cope with this pandemic that affected the whole world. COVID-19 vaccines with different features in the form of vector-mediated, messenger RNA (mRNA) or inactivated vaccines are being produced worldwide. CoronaVac® is an inactivated vaccine against severe acute respiratory syncytial coronavirus 2 (SARS-CoV-2) developed by Sinovac Biotech, China which was approved by World Health Organization (WHO) in June 2021. Vaccine Adverse Effect (VAE) is defined as "any adverse medical event that occurs after vaccination, which is thought to be due to a vaccine. The primary endpoint of our study was to evaluate the VAEs reported after the first dose and the second doses following the inactivated vaccine (CoronaVac®), which was administered to HCWs in our country as a dose of 3 µg twice, 28 days apart. The secondary endpoint was the comparison of the frequency of VAE development between groups according to socio-demographic characteristics.