Clinical trial NCT07026500: Clinical Trial for Batch Consistency of EV71 Vaccine
Official title: A Single-center, Randomized, Double-blind Clinical Trial to Evaluate the Safety and Batch Consistency of the EV71 Vaccine in Infants Aged 6 to 35 Months After Vaccination According to a Two-dose Immunization Schedule
Study type: INTERVENTIONAL
Overall status: COMPLETED
Phase: PHASE4
Conditions: EV71 Vaccine
Lead sponsor: Sinovac Biotech Co., Ltd
Sponsor class: INDUSTRY
First posted: 2025-06-18
Enrollment: 720
Sex: ALL
Minimum age (years): 6
Maximum age (years): 35
Standard ages: CHILD
Accepts healthy volunteers: yes
Allocation: RANDOMIZED
Intervention model: PARALLEL
Primary purpose: PREVENTION

Brief summary: This trial is designed as a single-center, randomized, double-blind study. A total of 720 infants aged 6 to 35 months are selected (with 240 subjects in each age group: 6-11 months, 12-23 months, and 24-35 months). Subjects from different age groups are randomly allocated to three batch groups in a 1:1:1 ratio, and receive two doses of the EV71 vaccine from the commercial production batch on days 0 and 30. After each vaccination dose, subjects will be observed for immediate reactions for 30 minutes and for solicited adverse events for the next 7 days, as well as for unsolicited adverse events over the 30 days following vaccination. All subjects will have blood samples collected on day 0 (pre-immunization) and day 60 for serum antibody testing. Additionally, 270 subjects will be selected, for additional blood sampling at various time points: 7 days, 14 days, and 30 days after the first dose, and 7 days and 14 days after the second dose, to assess the EV71 antibody levels at different timepoints following various doses of vaccination.


Eligibility criteria: Inclusion Criteria:

* Infants and young children aged 6 to 35 months.
* Able to provide legal identification.
* The guardian of the subject has the ability to understand and agrees to sign the informed consent form.

Exclusion Criteria:

* Previous vaccination with the EV71 vaccine.
* History of hand, foot, and mouth disease.
* History of allergies, asthma, including allergies to vaccines or vaccine components, and severe adverse reactions to vaccines, such as urticaria, difficulty breathing, angioedema, or abdominal pain.
* Congenital malformations or developmental disorders, genetic defects, severe malnutrition, etc.
* Autoimmune diseases or immune deficiencies/immunosuppression.
* Severe neurological disorders (epilepsy, convulsions, or seizures) or mental illness.
* History of thyroidectomy, asplenia, functional asplenia, or any condition leading to asplenia or splenectomy.
* Blood coagulation abnormalities diagnosed by a physician (such as clotting factor deficiencies, coagulopathies, platelet abnormalities) or evident bruising or bleeding disorders.
* Treatment with immunosuppressants, cytotoxic therapy, or inhaled corticosteroids within 6 months prior to enrollment (excluding corticosteroid nasal spray therapy for allergic rhinitis, or topical corticosteroid treatment for acute non-complicated dermatitis).
* Receipt of blood products within 3 months prior to vaccination with the trial vaccine.
* Receipt of other investigational vaccines within 30 days prior to vaccination with the trial vaccine.
* Receipt of live attenuated vaccines within 14 days prior to vaccination with the trial vaccine.
* Receipt of subunit or inactivated vaccines within 7 days prior to vaccination with the trial vaccine.
* Any acute illness or acute exacerbation of chronic illness within the past 7 days.
* Fever before receiving the investigational vaccine, with an axillary temperature \> 37.0°C.
* Any other factors that, in the investigator's judgment, make the subject unsuitable for participation in the clinical trial.

Primary outcomes:
measure: The GMT of EV71 neutralizing antibodies 30 days after complete immunization with the EV71 vaccine
timeFrame: 30 days after second dose
Secondary outcomes:
measure: Seroconversion rates, seropositive rates, and GMT of antibodies at 7 days, 14 days, and 30 days after the first dose of the EV71 vaccine
timeFrame: 7,14 and 30 days after the first dose
measure: Seroconversion rates, seropositive rates, and GMT of antibodies at 7 days and 14 days after the second dose of the EV71 vaccine, as well as the seroconversion rate and seropositive rate at 30 days post-vaccination
timeFrame: 7,14 and 30 days after the second dose
measure: The incidence of adverse reactions within 30 days after each dose of the EV71 vaccine
timeFrame: 30 days after each dose
measure: The incidence of solicited adverse events within 0-7 days after each dose of the EV71 vaccine
timeFrame: 7 days after each dose
measure: The incidence of serious adverse events during the safety observation period
timeFrame: 30 days after the second dose
Other outcomes:
Locations:
city: Dazhu
country: China
facility: Dazhu County Center for Disease Control and Prevention
Study officials:
References: