病毒不断变异 接种疫苗有效吗？专家：流感疫苗组分每年更新 匹配当季流行株

Core Viewpoint - The matching rate of the influenza vaccine for the H3N2 subtype has improved compared to previous years, with over 95% similarity to circulating strains, addressing public concerns about vaccine effectiveness against evolving viruses [1][2]. Group 1: Vaccine Effectiveness - The influenza vaccine is updated annually based on the World Health Organization's recommendations, ensuring better protection against the current circulating strains [1]. - Antibodies generated from the influenza vaccine typically decline after 6-8 months, necessitating annual vaccination for optimal protection during flu season [2][3]. - Even individuals who have previously contracted influenza should receive the vaccine, as different subtypes can circulate simultaneously, and immunity to one subtype does not confer protection against others [3]. Group 2: Current Influenza Situation - The overall influenza activity in the country is at a moderate level, with the H3N2 subtype accounting for over 95% of cases, while H1N1 and B type viruses are also present in smaller proportions [2]. - The winter and spring seasons are identified as high-risk periods for influenza and other acute respiratory infections, prompting health authorities to enhance vaccination efforts among vulnerable populations [3].