This study aims to assess the neutralizing antibody levels and prevalence risk of Japanese encephalitis among residents in low-endemic areas, as well as to evaluate the immunogenicity, safety, and immune persistence of the inactivated Japanese encephalitis vaccine across different age groups in healthy populations. The study uses an open-label, single-arm trial design with a sample size of 250 participants. Primary endpoints include pre- and post-vaccination serum neutralizing antibody levels, seroconversion rates, and incidence of adverse events.
This study aims to gain an in-depth understanding of neutralizing antibody levels against Japanese encephalitis among residents in low-endemic areas to assess potential outbreak risks and to evaluate the immunogenicity, safety, and immune persistence of the inactivated Japanese encephalitis vaccine across different age groups in a healthy population. This open-label, single-arm trial is structured in two phases: Phase I will involve stratified sampling of residents aged 6 years and older for serological testing, followed by administration of the inactivated JE vaccine to assess safety, with serological testing conducted 28 days post-vaccination. Phase II will conduct serological testing 365 days post-primary immunization to evaluate immune persistence. The target population includes residents aged 6 and older, divided into Group A (ages 6-17), Group B (ages 18-39), and Group C (ages 18+), with different vaccine dosages for each group. Inclusion criteria encompass age, health status, and informed consent, while exclusion criteria cover allergies, serious illness, and recent vaccination. Primary endpoints will include pre- and post-vaccination serum neutralizing antibody levels, seroconversion rates, average antibody levels, and post-vaccination adverse event incidence. The project is scheduled to begin in October 2024 and conclude in December 2026, with the primary research unit being the Liaoning Provincial Center for Disease Control and Prevention, aiming to provide a scientific basis for JE control and prevention in this region.
Study Type
INTERVENTIONAL
Allocation
NON_RANDOMIZED
Purpose
PREVENTION
Masking
NONE
Enrollment
250
The patient needs to receive 1 dose of inactivated Japanese encephalitis vaccine.
The patient needs to receive 2 doses of inactivated Japanese encephalitis vaccine, with an interval of 28 days.
The patient needs to receive 2 doses of inactivated Japanese encephalitis vaccine, with an interval of 7 days.
Liaoning Provincial Center for Disease Control and Prevention
Shenyang, Liaoning, China
Assessment of JE neutralizing antibody levels in low-prevalence areas to evaluate the risk of JE transmission.
Before administering the first dose of the vaccine, at least 3 ml of the recipient's venous blood will be collected. Transport the serum under frozen conditions to the testing laboratory for analysis. The serum Japanese encephalitis neutralizing antibodies will be detected using the Plaque Reduction Neutralization Test (PRNT50). A neutralizing antibody titer of \< 1:10 before vaccination is considered negative, while a titer of ≥ 1:10 after vaccination is considered positive. If the pre-vaccination antibody titer is ≥ 1:10, an increase of fourfold or more in the post-vaccination antibody titer is also considered a positive result.
Time frame: Prior to administration of the first vaccine dose.
Seroconversion rate and average neutralizing antibody levels against JE on the 28th day after vaccination.
After completing all doses of the trial, collect at least 3 ml of venous blood from the subjects on day 28. Transport the serum under frozen conditions to the testing laboratory for analysis. The serum Japanese encephalitis neutralizing antibodies will be detected using the Plaque Reduction Neutralization Test (PRNT50). A neutralizing antibody titer of \< 1:10 before vaccination is considered negative, while a titer of ≥ 1:10 after vaccination is considered positive. If the pre-vaccination antibody titer is ≥ 1:10, an increase of fourfold or more in the post-vaccination antibody titer is also considered a positive result.
Time frame: On the 28th day after vaccination.
Seroconversion rate and average neutralizing antibody levels against JE on the 365th day after vaccination.
After completing all doses of the trial, collect at least 3 ml of venous blood from the subjects on day 365. Transport the serum under frozen conditions to the testing laboratory for analysis. The serum Japanese encephalitis neutralizing antibodies will be detected using the Plaque Reduction Neutralization Test (PRNT50). A neutralizing antibody titer of \< 1:10 before vaccination is considered negative, while a titer of ≥ 1:10 after vaccination is considered positive. If the pre-vaccination antibody titer is ≥ 1:10, an increase of fourfold or more in the post-vaccination antibody titer is also considered a positive result.
Time frame: On the 365th day after vaccination.
Adverse event rate
1. The incidence, severity, and correlation of any adverse events (AEs) at the injection site (local) and non-injection site (systemic) within 30 minutes after each dose; 2. The incidence, severity, and correlation of AEs within 0-7 days after each dose; 3. The incidence and correlation of all AEs and serious adverse events (SAEs) occurring within 30 days after the complete vaccination.
Time frame: Within 30 days after vaccination.
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