Peer-reviewed article
Safety Profiles of Seasonal Influenza Vaccines in Chinese Children and Adolescents: A Pooled Analysis of Five Clinical Studies.
Hu L, Liu Y, Jia S, Wei M, Jin P et al. ·
Summary
Written by AI, not yet AICS's view · claude-haiku-4-5-20251001This study pooled safety data from five clinical trials of seasonal influenza vaccines given to nearly 2,900 Chinese children and adolescents aged 6-17 years. Overall, about one in four children experienced some adverse event after vaccination, but serious reactions were rare and grade 3 events uncommon. Different vaccine types caused different side effects: inactivated vaccines mainly caused fever and injection-site reactions, while the live vaccine caused respiratory symptoms. Among the inactivated vaccines tested, the quadrivalent subunit vaccine appeared to cause fewer local reactions than the trivalent split-virion vaccine.
Key points
- Overall adverse event incidence was 23.1% across all five vaccines, with no serious adverse events reported
- Grade 3 adverse events were uncommon (≤1.1%)
- Inactivated vaccines were associated with pyrexia and injection-site reactions
- Trivalent live attenuated influenza vaccine caused rhinorrhea, cough, and nasal congestion
- Quadrivalent inactivated subunit vaccine had lower odds of any adverse event and local adverse events compared with trivalent inactivated split-virion vaccine
Limitations
The study only reports short-term safety outcomes immediately following vaccination and does not assess vaccine effectiveness. The analysis is limited to Chinese children and adolescents, so findings may not generalise to other populations.
Abstract
Introduction Safety concerns remain an important barrier to pediatric influenza vaccination, yet directly comparable evidence across vaccine platforms, valency formulations, and administration routes remains limited. This study compared the safety profiles of five seasonal influenza vaccines in Chinese children and adolescents. Methods We pooled individual-level safety data from five clinical studies including participants aged 6-17 years. Adverse event (AE) incidences and 95% confidence intervals (CIs) were estimated using Clopper-Pearson methods, and multivariable logistic regression models were used to compare AE risks. Results Among 2885 participants, overall AE incidence was 23.1% (95% CI, 21.6-24.7%). Grade 3 AEs were uncommon (≤ 1.1%), and no serious AEs were reported. AE profiles differed across vaccine platforms: inactivated vaccines were mainly associated with pyrexia and injection-site reactions, whereas trivalent live attenuated influenza vaccine was characterized by rhinorrhea, cough, and nasal congestion. Compared with trivalent inactivated split-virion vaccine, quadrivalent inactivated subunit vaccine was associated with lower odds of any AE (aOR, 0.52; 95% CI, 0.35-0.79) and local AEs (aOR, 0.30; 95% CI, 0.17-0.52). Conclusions All five vaccines showed acceptable short-term safety, with platform-specific reactogenicity patterns. Among inactivated vaccines, the quadrivalent subunit formulation showed a relative local tolerability advantage.