There are many different types of influenza vaccines that can be chosen according to your situation. Generally, the self-funded influenza A+C vaccine is a conjugate vaccine, and its immunogenicity and durability of immunity are better than that of the free A+C polysaccharide vaccine. Generally, the A+C conjugate vaccine is mainly used for children and adults over six months of age, with two doses of basic immunization, each at an interval of not less than one month, and only one vaccination is recommended for children and adults over two years of age. The free A+C polysaccharide vaccine can be used to prevent epidemic meningitis caused by meningococci of groups A and C. However, its immunogenicity and persistence of immunity are not as good as those of the self-financed vaccine.