Inclusion Criteria:  Participants aged ≥ 72 months to < 75 months. Participants have completed routine immunization schedules in time. Participants are healthy native residents. Parents/guardians can understand the protocol requirements, provide informed consent, accept all scheduled visits, and comply with all trial procedures.  Exclusion Criteria:  History of neurological diseases or related symptoms. An acute illness with fever (temperature ≥ 37.1℃) or any acute onset of chronic diseases. Known impairment of immunologic function, or receipt of immunosuppressive therapy or immunoglobulin in the past 3 months. Known allergy to any constituent of the vaccine. Have been injected with other vaccines or any clinical trial drugs in the past 4 weeks. Any condition which, in the opinion of the investigator, would pose a health risk to the subject or interfere with the vaccine.