Hand, foot, and mouth vaccine is known clinically as EV71 vaccine. Hand, foot, and mouth disease is an infectious disease caused by a variety of viruses that is common in children under 5 years of age. The need for the HFMD vaccine is determined by the age of the child, the presence of a history of infection, and the presence of other contraindications. Therefore, the reason for not recommending HFMV should be the presence of contraindications in the patients themselves: 1. Due to the low incidence of HFMD in children and adults over 5 years of age, or in children who have already had HFMD, further HFMV vaccination is usually not recommended; 2. Patients who are known to be allergic to any of the components of EV71 vaccine, or who have fever, acute illness period, and acute exacerbation of chronic illness are not eligible for vaccination; 3. Patients with 3. Patients suffering from thrombocytopenia or bleeding disorders may bleed at the injection site when administered intramuscularly, so vaccination is not recommended; 4. Patients with immune deficiencies, such as HIV infection, or those undergoing immunosuppressive therapy, such as the use of immunosuppressive drugs, chemotherapy drugs, antimetabolites, corticosteroids, etc., may be affected by the vaccine after injection, so it is recommended that vaccination be administered after drug therapy is completed; 5. vaccination after the completion of medication; 5. Patients with uncontrolled epilepsy or patients with other progressive neurological diseases, such as Green-Barre syndrome, need to choose whether to be vaccinated under the advice of a doctor.