Research on the main factors influencing influenza vaccine effectiveness

Effectiveness of seasonal influenza vaccines varies greatly during the different flu seasons. Although the WHO assesses and updates influenza vaccine strains every year, the effectiveness of vaccine is sometimes not good. This review explores the various factors that influencing influenza vaccine effects in order to improve the effectiveness of influenza vaccines and provide a scientific basis for influenza vaccination. The results reveal that the degree of matching between epidemic strains and vaccine strains, pre-exposure (natural infection, vaccination), age, and immune status could all affect the vaccine effectiveness.