Does the Japanese encephalitis virus (JEV) vaccine provide cross-protection against severe dengue?

Medical Advisory BoardAll articles are reviewed for accuracy by our Medical Advisory Board
Educational purpose only • Exercise caution as content is pending human review
Article Review Status
Submitted
Under Review
Approved

Last updated: September 19, 2025 • View editorial policy

Personalize

Help us tailor your experience

Which best describes you? Your choice helps us use language that's most understandable for you.

Japanese Encephalitis Vaccine Does Not Provide Cross-Protection Against Severe Dengue

The Japanese encephalitis virus (JEV) vaccine does not provide reliable cross-protection against severe dengue and should not be used for this purpose. While both JEV and dengue virus belong to the same flavivirus family, current evidence does not support using JEV vaccination as a strategy to prevent severe dengue disease.

Evidence on Cross-Protection

Antibody Cross-Reactivity Without Protection

  • Studies examining cross-protection between related flaviviruses show that JEV vaccination does not induce sufficient protective neutralizing antibodies against dengue virus 1.
  • Despite successful immunization against JEV, protective neutralizing antibody titers to related flaviviruses like West Nile virus were not detected in vaccinated individuals 1.

Potential Risks of Cross-Reactivity

  • JEV vaccines can actually induce cross-reactive antibodies against dengue virus that may contribute to antibody-dependent enhancement (ADE) of dengue infection 2.
  • Research indicates that JEV vaccination might potentially increase the risk of symptomatic dengue through these cross-reactive ADE-prone antibodies 2.

Immunological Considerations

T-Cell Responses

  • T-cell responses to JEV in healthy JEV-exposed individuals differ significantly from those in recovered JE patients, with different targeting patterns and degrees of cross-reactivity to dengue virus 3.
  • While some T-cell cross-reactivity exists between JEV and dengue virus, the clinical significance for protection against severe dengue remains unproven 3.

Experimental Evidence

  • Although some laboratory studies in mice have shown that JEV prM-E antigen immunization might confer some protection against dengue virus challenge 4, these findings have not translated to demonstrated clinical protection in humans.
  • Recent research has focused on modifying JEV vaccines to reduce cross-reactive antibodies that could potentially enhance dengue infection 2.

Clinical Recommendations

  • For protection against dengue:

    • Use dengue-specific vaccines when indicated
    • Employ mosquito bite prevention strategies as recommended by the CDC 5
    • Consider appropriate personal protective measures including:
      • Using DEET-based repellents on exposed skin
      • Wearing long-sleeved clothing
      • Using bed nets in accommodations without screens or air conditioning

  • For protection against JEV:

    • JEV vaccination should be administered according to ACIP guidelines for:
      • Laboratory workers with potential exposure to infectious JEV 6
      • Travelers spending ≥1 month in endemic areas during transmission season 6
      • Short-term travelers with high-risk itineraries in endemic areas 6

Conclusion

While both JEV and dengue are flaviviruses with some antigenic similarities, the JEV vaccine has not been demonstrated to provide clinically meaningful protection against severe dengue. Current evidence suggests that cross-reactive antibodies induced by JEV vaccination might potentially increase dengue risk through antibody-dependent enhancement. For protection against dengue, dengue-specific vaccines and mosquito prevention measures remain the appropriate strategies.

References

5
Guideline

Mosquito-Borne Illness Prevention

Praxis Medical Insights: Practical Summaries of Clinical Guidelines, 2025

6
Guideline

Guideline Directed Topic Overview

Dr.Oracle Medical Advisory Board & Editors, 2025

Related Questions

When to use Mobic (meloxicam) for osteoarthritis or rheumatoid arthritis?
What is the hangout interval in the cardiac cycle, also known as the isovolumic relaxation time (IVRT)?
When is Lyrica (pregabalin) indicated for use?
Are incidental CT results significant in a 48-year-old perimenopausal female with an impending menstrual cycle?
When is Flexeril (cyclobenzaprine) recommended for use?
What are the differences between Baveno 5, Baveno 6, and Baveno 7 guidelines for managing portal hypertension?

Professional Medical Disclaimer

This information is intended for healthcare professionals. Any medical decision-making should rely on clinical judgment and independently verified information. The content provided herein does not replace professional discretion and should be considered supplementary to established clinical guidelines. Healthcare providers should verify all information against primary literature and current practice standards before application in patient care. Dr.Oracle assumes no liability for clinical decisions based on this content.

Have a follow-up question?

Our Medical A.I. is used by practicing medical doctors at top research institutions around the world. Ask any follow up question and get world-class guideline-backed answers instantly.

Ask Question