The flu vaccine needs to be given to babies over 6 months of age. This can be evaluated by the doctor at the vaccination station. According to the immunization program of the influenza vaccine manual, children between 6 months of age and 8 years of age who are vaccinated for the first time or who have been vaccinated with only one dose of influenza vaccine in the past should be vaccinated with 2 doses, with an interval of not less than 4 weeks between the 2 doses, and children aged 9 years old or above should be vaccinated with 1 dose, and then planned to be vaccinated every year thereafter. Influenza is characterized by severe symptoms, strong contagiousness and rapid spread, and severe infections can lead to complications such as mixed pneumonia and acute necrotizing encephalopathy, which are highly prevalent among children and the elderly. As influenza viruses are characterized by high variability, the vaccine composition may vary from year to year due to the different strains of viruses that are prevalent. Therefore, annual vaccination is required, preferably before the end of October, that is, before the high season of influenza.