流感季来了，打疫苗还来得及吗

Core Viewpoint - The flu season has begun in Henan, with the H3N2 strain being the predominant virus, raising concerns about vaccination timing and selection [1][2]. Group 1: Flu Season and Virus Information - The flu season in northern provinces typically runs from October to March, with a significant increase in flu cases observed in Henan, particularly among children [1]. - The main circulating strain in Henan is the H3N2 virus, which has previously co-circulated with the BV strain in 2023 [1]. Group 2: Symptoms and Complications - Common symptoms of the flu include high fever (39°C-40°C), headaches, muscle aches, fatigue, cough, and sore throat, with potential complications such as pneumonia and seizures [2]. - A case was highlighted where a 13-year-old developed pneumonia after delayed treatment for flu symptoms, emphasizing the need for timely medical attention [2]. Group 3: Vaccination Recommendations - Annual flu vaccination is the most effective and economical way to prevent the flu, especially for high-risk groups such as infants, the elderly, and those with chronic illnesses [2]. - Both trivalent and quadrivalent flu vaccines are approved in China, with sufficient supply currently available in Henan [2]. - The main difference between trivalent and quadrivalent vaccines is the number of virus subtypes they cover, and both types are effective in preventing the flu [2]. Group 4: Vaccination Timing - Flu vaccines typically take 2-4 weeks to generate antibodies, and it is recommended to get vaccinated as early as possible for optimal protection, although vaccination is still beneficial at any time during the flu season [2][3]. Group 5: Preventive Measures - In addition to vaccination, maintaining personal hygiene and enhancing physical health are crucial during the flu season, including avoiding crowded places, handwashing, and ensuring proper ventilation [3].