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

Abstract

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

• Varicella vaccine
• Vaccination
• Adverse events following immunization
• Surveillance