Clinical Trial for Batch Consistency of EV71 Vaccine

Phase 4

Completed

• Conditions: EV71 Vaccine
• Interventions: Biological: EV71 Vaccine

• Registration Number: NCT07026500
• Lead Sponsor: Sinovac Biotech Co., Ltd

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.

Detailed Description

Not available

Study Timeline

• Study Start: 2019-09-19
• Primary Completion: 2020-04-30
• Study Completion: 2020-05-31
• Status Verified: 2025-06
• Study First Submitted: 2025-06-10
• Study First Submitted QC: 2025-06-17
• Last Update Submitted: 2025-06-17
• Study First Posted: 2025-06-18
• Last Update Posted: 2025-06-18

Recruitment & Eligibility

• Status: COMPLETED
• Sex: All
• Target Recruitment: 720

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.

Study & Design

• Study Type: INTERVENTIONAL
• Study Design: PARALLEL

Arm && Interventions

Group	Intervention	Description
Batch group 1	EV71 Vaccine	EV71 vaccine first commercial production batch
Batch group 2	EV71 Vaccine	EV71 vaccine second commercial production batch
Batch group 3	EV71 Vaccine	EV71 vaccine third commercial production batch

Primary Outcome Measures

Name	Time	Method
The GMT of EV71 neutralizing antibodies 30 days after complete immunization with the EV71 vaccine	30 days after second dose

Secondary Outcome Measures

Name	Time	Method
Seroconversion rates, seropositive rates, and GMT of antibodies at 7 days, 14 days, and 30 days after the first dose of the EV71 vaccine	7,14 and 30 days after the first dose
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	7,14 and 30 days after the second dose
The incidence of adverse reactions within 30 days after each dose of the EV71 vaccine	30 days after each dose
The incidence of solicited adverse events within 0-7 days after each dose of the EV71 vaccine	7 days after each dose
The incidence of serious adverse events during the safety observation period	30 days after the second dose

Trial Locations

Locations (1)

Dazhu County Center for Disease Control and Prevention; 🇨🇳 Dazhu, China

Dazhu County Center for Disease Control and Prevention

🇨🇳Dazhu, China