The influenza vaccines now approved for marketing in China are trivalent inactivated influenza vaccine (IIV3), tetravalent inactivated influenza vaccine (IIV4) and nasal spray trivalent live attenuated vaccine (LAIV3), all of which can be used to prevent the infection of influenza A (H3N2) virus, and are generally not recommended on a priority basis, and can be voluntarily vaccinated with any of the influenza vaccines. According to the components contained in the vaccine, influenza vaccines include trivalent and quadrivalent. The trivalent vaccine contains influenza A (H1N1), H3N2, and one of the influenza B viruses, while the quadrivalent vaccine adds one of the influenza B viruses, and both types of vaccines provide protection against influenza infection. The trivalent inactivated influenza vaccine is available for people ≥6 months of age; the nasal spray trivalent live attenuated vaccine is available for people 3-17 years of age; and the quadrivalent inactivated vaccine is available for people ≥36 months of age. Usually, antibodies with protective level can be produced 2~4 weeks after influenza vaccination, and antibody titers begin to decline after 6~8 months. To ensure that the vaccinees are immunized before the influenza season, it is recommended to complete the immunization before the end of October. People who are allergic to any of the ingredients in the vaccine are prohibited from receiving the vaccine. For people with mild to moderate acute illness with or without fever symptoms, it is recommended to receive the vaccine after the symptoms have subsided. It is recommended to ask the doctor before vaccination and to proceed with the vaccination if contraindications are ruled out.