Objective To analyze the protective effect of different types of influenza vaccines (InfV) against influenza A among the individuals aged between 3‒17 years old, and to provide a scientific basis for the prevention and control of influenza in the future.

Methods A retrospective cohort study was conducted to collect data on the incidence and InfV vaccination of the individuals aged between 3‒17 years during the influenza epidemic season from 2022 to 2023. Vaccine effectiveness (VE) was calculated, and a log-binomial regression model was used to calculate the corrected VE.

Results The incidence rate of influenza in InfV vaccinated and un-vaccinated groups was 7.32% (1 937/ 26 446) and 9.65% (4 421/45 837), respectively. After adjusting for age and gender factors, the unadjusted VE (95%CI) was 54.57% (52.24%‒56.78%). The unadjusted VE (95%CI) was 53.66% (50.36%‒56.74%) for males and 55.60% (52.24%‒58.72%) for females, respectively. The unadjusted VE (95%CI) for the age group of 3‒ years, 6‒ years, 9‒ years, 12‒ years, and 15‒17 years were 64.08% (60.89%‒67.01%), 57.40% (53.71%‒60.80%), 57.77% (52.49%‒62.47%), 24.36% (9.49%‒36.79%), and 24.09% (-17.59%‒51.00%), respectively. The unadjusted VE (95%CI) for quadrivalent split-virion inactivated influenza vaccine, trivalent split-virion inactivated influenza vaccine, trivalent subunit influenza vaccine, and trivalent live attenuated influenza vaccine were 53.84% (51.32%‒56.24%), 62.17% (56.28%‒67.26%), 79.83% (69.94%‒86.46%), and 31.59% (19.07%‒42.18%), respectively.

Conclusion The InfV used during the 2022‒2023 influenza season had a good protective effect against influenza A among the individuals aged between 3‒17 years old, especially in those aged between 3‒11 years old.