Tetanus Clinical Trials

• Age Requirement: volunteers aged 4-6 years, 18-24 months, and 2 months.

• History of preventive inoculation: (1)children aged 4-6 years who have completed immunization with 4 doses of DTP vaccine or another combination vaccine containing DTP antigen components in accordance with the National Immunization Program, and who have not yet received the fifth dose of DTP vaccine; (2)children aged 18-24 months have completed basic immunization with DTP vaccine or another combination vaccine containing DTP antigen components (3 doses) and basic immunization with poliovirus vaccine (3 doses) in accordance with the National Immunization Program, and have not yet received a booster dose of DTP vaccine (the 4th dose) or a booster dose of poliovirus vaccine (the 4th dose); (3) infants aged 2 months have not yet received vaccines containing DTP antigen components, vaccines containing poliovirus antigen components, 13-valent pneumococcal polysaccharide conjugate vaccine, haemophilus influenzae type b conjugate vaccine, or group A and C meningococcal and haemophilustype b conjugate vaccine.

• Provision of Legal Identification: participants and their legal guardians or appointed representatives must provide valid legal identification documents.

• Informed Consent: participants, legal guardians, or appointed representatives of volunteers must have the capacity to understand the informed consent document and the research process, voluntarily participate, sign the informed consent form, and be able to comply with the requirements in the study as well as complete relevant visits on time.

• 2 months old: full term infant (37 weeks ≤ gestational age \< 42 weeks) with a birth weight ≥ 2500 g.