Prevalence and Risk Factors of CoronaVac Side Effects: An Independent Cross-Sectional Study Among Healthcare Workers in Turkey

Background: COVIC-19 vaccine hesitancy is a serious threat to mass vaccination strategies that need to be accelerated currently for achieving a substantial level of community immunity. Independent (non-sponsored) studies have a great potential to enhance public confidence in vaccines and accelerate their uptake process. Methods: A nationwide cross-sectional study for the side effects (SE) of CoronaVac was carried out in February 2021 among Turkish healthcare workers who got recently vaccinated. The questionnaire inquired about local and systemic SEs that occurred in the short-term, within four weeks, following vaccination. Findings: A total of 780 healthcare workers were included in this study; 62.5% of them experienced at least one SE. Injection site pain (41.5%) was the most common local SE, while fatigue (23.6%), headache (18.7%), muscle pain (11.2%) and joint pain (5.9%) were the common systemic SE. Female healthcare workers (67.9%) were significantly more affected by local and systemic SEs than male colleagues (51.4%). Younger age, previous infection, and compromised health status (chronic illnesses and regular medicines uptake) can be associated with an increased risk of CoronaVac SEs. Interpretation: The independent research shows a higher prevalence of CoronaVac SEs than what is reported by phase 1 – 3 clinical trials. In general, the results of this study confirm the overall safety of CoronaVac and suggest potential risk factors for its SEs. Gender-based differences and SEs distribution among age groups are worth further investigation. Trial Registration: The study protocol was registered in the National Library of Medicine (NLM) registry – NCT047706156 Funding Statement: This study was supported by the INTER-EXCELLENCE grant number LTC20031 — "Towards an International Network for Evidence-based Research in Clinical Health Research in the Czech Republic". Declaration of Interests: None to declare. Ethics Approval Statement: The study protocol was reviewed and approved by the General Directorate of Health Services of the Turkish Ministry of Health within the scope of the Public Health Law no. 1593; additionally, it had been approved by the Ethics Committee of the Faculty of Medicine, Masaryk University (MUNI) on January 20th, 2021 (Ref. 2/2021).(16) All the participants had to provide their informed consent digitally before joining the study, and the data was stored and handled by MUNI in compliance with the General Data Protection Regulation (GDPR).(