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Updated: Jun 12, 2026
09:37
Detection of Polyfunctional T Cells in Children Vaccinated with Japanese Encephalitis Vaccine via the Flow Cytometry Technique
Published on: September 23, 2022
[Long-term seroprotection against Japanese encephalitis using an inactivated vaccine (Jevax)]
D Van der Vliet1, A Simons de Fanti, S Murri
1Institut Pasteur, Centre médical, Centre d'infectiologie Necker-Pasteur, Paris.
Summary
Long-term protection from the Japanese encephalitis vaccine (Jevax) depends on receiving multiple doses. Even frequent travelers need repeated Jevax boosters for sustained seroprotection against Japanese encephalitis.
Area of Science:
- Immunology
- Vaccinology
- Virology
Context:
- Japanese encephalitis vaccine (Jevax), an inactivated vaccine using the Nakayama strain, was the sole option in France until 2007.
- Uncertainty existed regarding the duration of seroprotection and optimal booster timing for travelers from non-endemic regions.
Purpose:
- To assess neutralizing antibody levels in individuals vaccinated with Jevax.
- To determine factors influencing long-term seroprotection after Jevax immunization.
Summary:
- A retrospective study measured antibody levels in 71 Jevax-vaccinated subjects preparing for missions to Japanese encephalitis areas.
- 69% maintained protective antibody levels (≥20) a median of 4 years post-vaccination.
- Multivariate analysis identified the total number of Jevax vaccinations as the sole factor correlated with sustained seroprotection.
Impact:
- Findings indicate that repeated Jevax booster injections are crucial for achieving long-term seroprotection, even with frequent virus exposure.
- The interval between booster doses did not correlate with seroprotection duration.
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