Influenza vaccine is usually best injected in September~October every year. China’s annual influenza epidemic season is winter and spring, 1~2 months before the peak of the influenza epidemic, the influenza vaccine can more effectively play the protective role of the vaccine, so every year in September~October is the best time to get vaccinated against influenza. If effective immunity is produced after injection, the protective effect of influenza vaccine lasts for about one year. Both the World Health Organization and the Center for Disease Control in China recommend influenza vaccination, especially for young children, those with underlying diseases, the elderly and the infirm, and those with low immunity, because not only are the clinical symptoms of influenza virus infection more severe than those of a common cold, but it is also easy to be complicated by serious complications such as pneumonia, encephalitis, myocarditis, pericarditis, etc., which can even be life-threatening. Influenza vaccination is currently the most important and effective measure to prevent influenza, and it is recommended to consult a doctor before vaccination.