Phase I/II Clinical Trial of Diphtheria-Tetanus-Pertussis (Reduced Dose) Vaccine

Inclusion Criteria: * Age Requirement: volunteers aged 6 years and above * Provision of Legal Identification: volunteers 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. Exclusion Criteria: * Subjects whose physical examination, vital signs check, or laboratory test results are abnormal and have clinical significance, and are determined by the researcher to be unsuitable for participation in the clinical trial. * Subjects who have received any vaccine within 30 days (including the 30th day) before enrollment, or those who plan to receive other vaccines within 30 days (including the 30th day) after receiving the investigational vaccine. * Subjects who have experienced acute diseases (such as fever) or acute exacerbations of chronic diseases within 3 days before enrollment (including the third day). * Subjects who have had contact with patients clearly diagnosed with pertussis, diphtheria or tetanus within 30 days before enrollment. * Individuals who have been clinically diagnosed with diphtheria or tetanus within 10 years before enrollment, or with pertussis within 5 years; or t…