全国流感阳性率接近45%，12月迎来高峰

Core Insights - The flu positivity rate in emergency departments across China has reached nearly 45%, indicating a significant rise in flu cases and entering a moderate epidemic level, with some provinces experiencing high epidemic levels [1][2] Group 1: Flu Activity and Trends - The flu activity is rapidly increasing in both northern and southern regions of China, with some provinces expected to reach peak flu levels by mid-December, while most provinces will see peaks in late December [2] - The current flu season is characterized by the predominance of the H3N2 subtype, differing from the previous season which was dominated by the H1N1 subtype, and there is a co-circulation of H1N1 and B type flu viruses [6] Group 2: Virus Evolution and Vaccine Efficacy - The flu virus is undergoing minor changes, known as antigenic drift, but these changes do not indicate a significant increase in virulence or transmissibility [3][7] - Current monitoring data suggests that the circulating H3N2 virus strains still show good antigenic match with the vaccine strains, making the vaccine effective for this season [7] Group 3: Treatment and Prevention - Treatment for flu typically requires antiviral medications, while common colds are usually self-limiting and do not require specific antiviral treatment [8] - Common antiviral medications for children include neuraminidase inhibitors like Oseltamivir and polymerase inhibitors like Baloxavir, both of which are considered safe for use in children [10] - Preventive measures include regular hand washing, avoiding crowded places, and wearing masks when necessary, along with annual vaccination against flu and pneumonia for high-risk groups [12][13]