Surveillance of adverse events following varicella vaccine immunization in Jiangsu province, China from 2017 to 2023

Abstract

To assess the safety of varicella vaccine (VarV) by conducting post-marketing surveillance on adverse events following immunization (AEFI) in Jiangsu Province, China.

Methods: We utilized the AEFI Information System of mainland China to monitor and categorize adverse reactions associated with VarV.

Results: The incidence rate of AEFI was significantly higher after the first dose (48.79/100,000 doses) compared to the second dose (45.18/100,000 doses) (χ² = 4.63, P = 0.031). Regional variations in AEFI incidence were observed within Jiangsu Province. Common reactions comprised 90.96% of AEFIs, while rare reactions and coincidental events accounted for 6.59% and 0.51%, respectively. Notably, there were no adverse events linked to vaccine quality, program errors, psychogenic reactions, or fatalities. Over 96% of AEFIs occurred within three days of VarV administration, with redness at the injection site (2.6 cm to 5 cm in diameter) being the most frequently observed symptom.

Conclusion: VarV demonstrates a commendable safety profile. Although there was a slight increase in AEFI incidence between 2022 and 2023, common vaccine reactions were predominantly observed, and the rates of rare reactions remained very low.

Keywords: Adverse events following immunization; Surveillance; Vaccination; Varicella vaccine.