Determining Long-Term Safety and Efficacy of Japanese Encephalitis Vaccine When Given With Measles Vaccine
Condition: Encephalitis, Japanese B
MeSH terms: Measles; Encephalitis, Japanese; Encephalitis
Study type: Interventional
Phase: Phase 3

Summary: 
      The previously conducted JEV01 study looked at the immunogenicity and safety of the
      concurrent administration of Japanese Live Attenuated SA 14-14-2 and measles vaccines at the
      one month post vaccination time point. The purpose of the JEV01 study was to help ensure the
      safety of SA 14-14-2 simultaneously administered with measles vaccine, paving the way for its
      use in routine EPI programs. As a follow-on to JEV01, this study will enroll those infants
      who received both vaccines and completed the JEV01 study. This study, however, will provide
      crucial data to help ensure the long-term immunogenicity of the concurrent administration of
      these vaccines and provide valuable information to determine the use of these vaccines in
      routine immunization programs. This study is planned because in the original protocol for
      JEV01, long-term data points were not included. The hypothesis is that children who receive
      JE live attenuated SA 14-14-2 vaccine and measles vaccine at the same time have long-term (24
      and 36 months post vaccination) protection against these diseases at the same level as those
      who receive the vaccines at different intervals.
    

Detailed description: 
      Japanese encephalitis is the leading cause of viral neurological disease and disability in
      Asia. The severity of sequelae, together with the volume of cases, make JE the most important
      cause of viral encephalitis in the world. Approximately 3 billion people-including 700
      million children-live in Asian areas at risk for JE. JE most commonly infects children
      between the ages of 1 and 15 years, and can also infect adults in areas where the virus is
      newly introduced. More than 50,000 cases are reported annually and cause an estimated 10,000
      to 15,000 deaths. This figure is believed to represent only a small proportion of the disease
      burden that actually exists.

      An effective vaccine has existed since 1941, but has not reached the poorest countries in
      Asia. During the 60 years that the vaccine has been available, JE has infected an estimated
      10.5 million children, resulting in more than 3 million deaths and more than 4 million
      children living with long-term disabilities. Control of this disease has been limited due to
      poor disease surveillance, a limited and unstable vaccine supply, lack of guidance and
      programmatic support for immunization, and limited advocacy.

      A successful vaccine should be safe, efficacious, affordable, administered in a single dose,
      and easily incorporated into the routine Expanded Programmes on Immunization (EPI) programs.

      This trial is designed to determine the potential interference between the measles vaccine
      and the Japanese encephalitis vaccine at 12, 24, and 36 months post-vaccination. As these
      vaccines will be used in routine EPI systems at the same time, similar to how measles and
      yellow fever vaccine (also a Flavivirus) are administered, it is imperative to collect
      long-term data showing that neither vaccine interferes with seroconversion of the other when
      co-administered.This information will help to ensure subject safety and facilitate
      programmatic efficiency, reducing the number of immunization visits for both parents and
      health care workers.
    

Intervention name(s): Live attenuated SA 14-14-2 vaccine
Intervention type(s): Biological
Intervention description(s): Live attenuated SA 14-14-2 vaccine coadministered with live measles vaccine (experimental Group)
Allocation: Randomized
Intervention model: Factorial Assignment
Masking: None (Open Label)
Primary purpose: Prevention
Keywords: Japanese Encephalitis; Japanese B Encephalitis; Japanese B Viral Encephalitis; Viral Encephalitis, Japanese B