[Articles] Duration of the serological response and effectiveness of the inactivated influenza vaccine in healthy adults aged 18–65 years: a systematic review and meta-analysis

IIV-induced HAI titres in healthy adults aged 18–65 years persisted 5–7 months after vaccination, but might not be significantly sustained at 11–13 months. For influenza A/H3 and influenza B, there was a significant decline in vaccine effectiveness beyond 5 months after vaccination. Evaluating the temporal changes in vaccine effectiveness remains challenging due to methodological biases; a greater understanding is needed to optimise vaccine design and timing to maximise effectiveness throughout the influenza season.