Core Viewpoint - The article highlights the rising trend of influenza cases in southern China, particularly in Guangdong Province, with a recommendation for increased vaccination and preventive measures as the flu season approaches [3][4]. Group 1: Current Situation of Influenza - Guangdong Province is currently experiencing an influenza outbreak, primarily caused by the H3N2 strain, with a noted risk of outbreaks in densely populated areas [3]. - Monitoring data from the China CDC indicates that while northern provinces show low levels of flu activity, southern provinces are seeing an increase [3]. - Clinical observations report a significant rise in flu patients, with symptoms including fever, sore throat, headache, body aches, and fatigue [3]. Group 2: Vaccination Recommendations - The chief expert from Guangdong's CDC recommends flu vaccination as the most effective preventive measure against influenza and its complications, urging all individuals aged six months and older to get vaccinated unless contraindicated [4]. - High-risk groups, including children under five, the elderly, and individuals with chronic diseases, should be prioritized for vaccination [4]. - Vaccination should ideally be completed before the flu season begins, as protective antibodies typically develop 2 to 4 weeks post-vaccination [4]. Group 3: Types of Influenza Vaccines - Influenza vaccines are categorized into trivalent and quadrivalent types, with quadrivalent vaccines providing coverage for an additional strain of B influenza [5]. - Vaccines are further divided into inactivated and live attenuated types, with inactivated vaccines containing "killed" viruses and live attenuated vaccines containing weakened viruses [5]. - The majority of inactivated vaccines on the market are split vaccines, which are produced by breaking down the virus, while subunit vaccines involve further purification of the antigens [5]. Group 4: Safety and Administration of Vaccines - Both split and subunit vaccines are considered safe and effective, with the main differences lying in production methods, costs, and age suitability [5]. - For live attenuated vaccines administered via nasal spray, specific populations are advised against vaccination, including those with compromised immune systems and certain medical histories [6][7].

Core Insights - The flu season is currently active in Guangdong Province, primarily driven by the H3N2 strain, with a noted increase in flu cases in outpatient departments [1][2] - The flu peak season in southern regions has arrived earlier this year, indicating a potential increase in flu intensity, necessitating early preventive measures [1][2] Vaccine Recommendations - Vaccination is the most effective method for preventing flu and its complications, recommended for all individuals aged six months and older, especially high-risk groups [2] - High-risk groups include children under five, the elderly, and individuals with chronic conditions such as cardiovascular diseases and diabetes [2] Vaccine Types and Administration - Various flu vaccines are approved in China, including trivalent inactivated vaccines, quadrivalent inactivated vaccines, and trivalent live attenuated vaccines [2][3] - The main difference between inactivated and live attenuated vaccines lies in their production methods and administration routes, with inactivated vaccines administered via intramuscular injection and live attenuated vaccines via nasal spray [2][3] Vaccine Safety and Efficacy - Both inactivated and live attenuated vaccines are considered safe and effective, with no significant differences in protective efficacy [3] - The majority of inactivated vaccines on the market are split vaccines, which are produced using a mature technology [3] Contraindications for Live Attenuated Vaccines - Specific populations are advised against receiving live attenuated vaccines, including immunocompromised individuals, children on aspirin therapy, and pregnant women [4][5]