Immunogenicity and Safety of Inactivated Vero Cell Derived Japanese Encephalitis Vaccine in Thai Children

Phase 3

Completed

Brief Summary: Japanese encephalitis (JE) is the main cause of viral encephalitis in many countries of Asia including Thailand. Estimated annual mortality ranges from10,000-15,000 deaths, while the total number of clinical cases is about 50,000. Of these cases, about 50% result in permanent neuropsychiatric sequelae. The disease occurs mostly among children aged \<10 years. There is no specific antiviral treatment for JE. Vaccination is the single most important control measure. This study aims to evaluate the immunogenicity and safety of inactivated Vero cell derived JE vaccine (Beijing P-3 strain) produced by Liaoning Cheng Da Biotechnology Co., Ltd, China "JEVAC" in Thai children.

152 healthy Thai children aged between 1-3 years will be vaccinated with "JEVAC" in a dose of 0.5 mL. subcutaneously on Day 0, 1-4 weeks later and a booster vaccination at one year (totally 3 doses). Two mL. of blood will be drawn on Day 0, 4 weeks after second dose, at one year on booster vaccination day and 4 weeks after the booster (totally 8 mL. of 13 months study period) for determination of JE neutralizing antibodies (PRNT50) using Beijing P3 strain. Adverse events will be observed for 28 days after each vaccination. Serious adverse events will be observed throughout the study period.

Recruitment & Eligibility

Inclusion Criteria

Exclusion Criteria

Known serious underlying diseases such as nervous system, heart, kidney and liver diseases.
Known hypersensitivity to JE vaccine composition such as human albumin, dextran 40, etc.
Previous history of JE disease.
Receive the blood component within the past 3 months,
Known history of immunocompromised conditions such as HIV/AIDS, malignancy.
Under treatment of immunosuppressive drugs such as systemic corticosteroid and anti-neoplastic drug.
Febrile illness (temperature ≥37.5°C) or acute illness/infection on the day of vaccination
Plan to leave the study area before the end of study period.
Participating in other clinical trials.

Arm && Interventions

Group	Intervention	Description
JEVAC	JEVAC	JEVAC 0.5 mL/ dose subcutaneously injected on upper thigh at D0, 1-4wk, and 1 year

Primary Outcome Measures

Name	Time	Method
Seroconversion Rate After Primary Vaccination	28 days after second dose of JEVAC	To determine the seroconversion rate by using neutralizing antibody (NT) against JE virus (Beijing P3 strain) JE virus from \<10 on before first vaccination To \>= 10 at 28 days after second vaccination (primary vaccination). Those who have NT titer \>=10 before first vaccination, will not be included in immunogenicity evaluation.

Secondary Outcome Measures

Name	Time	Method
Adverse Events of Vaccine	7, 14, 28 days after each vaccination and throughout the study period for local, solicited systemic, unsolicited systemic and serious adverse events, respectively	To determine the adverse events of JEVAC
Geometric Mean Titer of NT After Primary and Booster Vaccination	28 days after second vaccination, before and 28 days after booster vaccination with JEVAC	To determine the geometric mean titers (GMT) of neutralizing antibody of JEVAC 1 month after primary and then before and after booster vaccinations.
Neutralizing Antibody Persistence One Year After the Primary Vaccination	1 year after primary vaccination	To determine the neutralizing antibody persistence one year after the primary JEVAC vaccination.