Abstract
BACKGROUND: Varicella, caused by the varicella-zoster virus, is a highly contagious pediatric infection that can lead to severe complications. SKYVaricella Inj. (SK bioscience Co., Ltd, Incheon, Korea), a live-attenuated varicella vaccine developed by SK bioscience, was approved in Korea in 2018. This post-marketing surveillance study aimed to evaluate the safety profile of SKYVaricella Inj. (SK bioscience Co., Ltd, Korea) in children aged 12 months to 12 years in routine clinical practice. MATERIALS AND METHODS: This multicenter, prospective, non-interventional study was conducted across 25 sites in Korea from June 4, 2018, to June 3, 2022. A total of 623 subjects were included in the safety analysis. Adverse events (AEs), including those assessed as adverse drug reactions (ADRs), and serious adverse events (SAEs), were monitored for 42 days post-vaccination. Events were further categorized by causality and expectedness based on regulatory definitions. Descriptive statistics were used to summarize AE incidence and to explore potential associations with participant characteristics. RESULTS: Among the 623 participants, 263 (42.2%) reported 514 AEs, and 56 (9.0%) experienced ADRs. The most frequently reported ADRs were injection site pain (4.0%), erythema (3.9%), and irritability (3.7%). Two SAEs (0.3%) - bronchitis and hand-foot-and-mouth disease - were reported and assessed as unrelated to vaccination. Varicella-like rashes occurred in 10 subjects (1.6%) and were mostly mild or moderate in severity. No unexpected serious adverse drug reactions were observed. CONCLUSION: SKYVaricella Inj. (SK bioscience Co., Ltd, Korea) demonstrated an acceptable safety profile in pediatric use in Korea, with most AEs being mild and consistent with expected vaccine-related reactions. Continued pharmacovigilance and larger-scale studies are warranted to further support its long-term public health impact.