Acute Adverse Events After BNT162b2 mRNA and Inactivated SARS-CoV-2 Vaccines in People who had COVID-19 Vaccines

Objective: Considering the classical vaccine development processes, COVID-19 vaccines were developed in a concise period. However, safety cannot be compromised for the rapid development of vaccines. Therefore, we aimed to in-vestigate and compare the incidence of acute adverse events between vaccine doses and vaccine types in patients who were previously diagnosed with COVID-19 and those who were not.Method: The study was conducted prospectively between July 1, 2021, and October 31, 2021. Participants who were vaccinated with the Pfizer-BioNTech BNT162b2 mRNA COVID-19 vaccine and the Sinovac inactivated SARS-CoV-2 vaccine (CoronaVac) were recruited in the cohort study. The cohort was divided into two vaccine categories and sub-branches: those with COVID-19 in each vaccine category and those without. Eight days after the vaccination, all participants in the cohort were provided with an assessment questionnaire regarding the adverse events they experienced.Results: A total of 1607 vaccine doses were followed in the study, 18.7% (n=301) of which were the inactivated SARS-CoV-2 vaccine and 81.3% (n=1306) were the BNT162b2 vaccine. According to the statistics, the risk of developing adverse events with the BNT162b2 vaccine was shown to be 5.8 times higher than the inactivated SARS-CoV-2 vaccine (OR: 5.83; 95% CI: 4.34-7.84). In addition, the risk of suffering such adverse events was 1.6 times higher in patients who were previously diagnosed with COVID-19 (OR: 1.61; 95% CI: 1.29-2.00) as opposed to patients who were not.Conclusion: Based on the results, we can conclude that acute adverse events were more prevalent after vaccination with the BNT162b2 vaccine than the inactivated SARS-CoV-2 vaccine. Furthermore, compared to those who did not have COVID-19, it was evident that patients who were previously diagnosed with COVID-19 were prone to experience mild, temporary, and manageable adverse events.