To Evaluate the Lot-to-lot Consistency of Immunogenicity, Safety, and Immune Persistence of Three Consecutive Commercial Manufacturing Batches of Inactivated Enterovirus 71 Vaccine (Human Diploid Cell) in Children Aged 6-35 Months in a Randomized, Blinded Study
This study is a randomized, blinded study to evaluate the lot-to-lot consistency of immunogenicity, safety, and immune persistence of three consecutive manufacturing lots of EV71 vaccine, in 1500 children aged 6-35 months. The primary immunogenicity endpoint is the anti-EV71 neutralizing antibody geometric mean titer (GMT) 30 days after the final dose. The secondary immunogenicity endpoints are the geometric mean fold increases and seroconversion rates of anti-EV71 neutralizing antibodies 30 days after the final dose. The immune persistence endpoints are the seropositive rates as well as GMT of anti-EV71 neutralizing antibodies 12 and 24 months after the final dose. The safety endpoints are the number of adverse events/reactions within 30 minutes after each dose, the number of solicited adverse events/reactions within 7 days after each dose, the number of unsolicited adverse events/reactions within 30 days after each dose, and the number of serious adverse events (SAE) from the first dose to 6 months post the final dose.
• Age Requirement: Children aged 6 to 35 months at the time of enrollment.
• Provision of legal Identification: Volunteers and their legal guardians or appointed representatives must provide valid legal identification documents.
• Informed Consent: 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 study's requirements and complete relevant visits on time.
• Temperature Requirement: Axillary body temperature prior to vaccination is less than 37.3°C.