面对面丨今年流感为何来势汹汹？打了疫苗为何仍会“中招”？专家详解

Core Viewpoint - The current flu season in China is experiencing a significant rise in cases, with 17 provinces reporting high levels of flu activity and a positive rate of 51% among flu-like cases in emergency departments [1][11]. Group 1: Flu Activity and Trends - Since late October, flu activity in Beijing has been on the rise, entering an epidemic phase by mid-November, approximately four weeks earlier than the previous year [2]. - Nationwide, there have been 1,541 reported outbreaks of flu-like cases, nearly 50 times higher than the same period last year, with 80% occurring in primary and secondary schools [11]. Group 2: Severity and Risk of Cases - Approximately 10% of flu cases may require hospitalization, with a small percentage classified as critical cases needing intensive care [6]. - The overall mortality rate for flu is less than 0.1%, but high-risk groups, particularly those requiring hospitalization, need close monitoring [6]. Group 3: Virus Types and Characteristics - The dominant strain this winter is the H3N2 subtype of the influenza A virus, accounting for over 95% of cases, with some circulation of H1N1 and influenza B viruses [8]. - Flu is characterized by strong transmissibility and severe symptoms, primarily affecting the winter and spring seasons [8]. Group 4: Vaccination and Prevention - Vaccination is recommended before the flu season peaks, ideally in September or October, to reduce infection risk and severity [22]. - The effectiveness of the flu vaccine can vary based on the accuracy of predictions regarding circulating strains, with protection rates potentially exceeding 60% if predictions are accurate [25][27]. Group 5: Treatment and Management - The optimal time for antiviral treatment is within 48 hours of symptom onset, as antiviral medications are most effective when administered early [29]. - The flu season is expected to continue for several weeks, with northern regions nearing a peak and southern regions still on the rise [34][35].