Adverse Events Following COVID-19 Vaccination in Anambra State, South East Nigeria

The use of safe and effective vaccination is critical to control of pandemics. Vaccines remain the bedrock in management of infectious diseases outbreaks. There has always been hesitancy to vaccination due to the fear of adverse events. It is therefore necessary that post vaccination adverse events be studied for effective enlightenment of the general populace. Objective: We aimed to investigate the adverse reactions following COVID-19 vaccination in Anambra state, South East Nigeria. Methods: Using a cross-sectional study design, 433 subjects aged 18years or older who had received any dose of the four COVID-19 vaccines (Moderna, Astra Zeneca, Pfizer and J&J (Janssen) were selected using a multi-stage sampling technique. The subjects were interviewed about COVID-19 vaccine related adverse reactions using self-administered questionnaire. Descriptive statistics (mean, standard deviation) and analytical statistics were performed and level of significance set at < 0.5 using SPSS V24. Results: Of the 433 subjects finally studied, 62.8% were females and 22.4% were married. About 69% of them had tertiary education.  Those who received the second dose of their respective vaccines were 44.8% while 11.5% had received a booster dose. Approximately half (50.3%) of the COVID-19 vaccines had adverse events. The most common types of adverse events (AEs) were local pain at injection site (62.1%) followed by headache (54.3%) and then fatigue (50.1%). Majority of the adverse events were mild to moderate in severity.  Those who had only local adverse events were 70.2% while 45% had systemic adverse events. Conclusion: In this study, severe adverse events were rare, even after the second dose. Most of the adverse events were mild to moderate in severity and therefore awareness campaign should be created to enlighten the community about the adverse effects of COVID-19 vaccines.