The influenza virus mutates at a fairly rapid rate, and even if the vaccine is updated every year, it cannot guarantee that the vaccination covers all the "seasonal epidemic models. " Influenza vaccination can neither guarantee 100% of the flu, but also may cause side effects such as low fever in the vaccinated population. There is no need to get a flu vaccine. If the following options are true, the above conclusions cannot be effectively refuted:. ['Influenza vaccination can reduce the risk of serious complications due to influenza in children, chronic disease patients and other high-risk groups.', 'Vaccination with seasonal flu can reduce the risk of influenza virus infection in susceptible people.', 'Only a very small number of people will have a systemic reaction after receiving the flu vaccine, and it can be relieved in a day or two, which is much lighter than the symptoms of the flu.', 'People who have recovered from the disease can get a certain degree of immunity and will not be infected by the same flu virus again within 1 year.']