Imojev (live attenuated Japanese encephalitis chimeric virus vaccine) / Sanofi - LARVOL DELTA

Long-term Immunogenicity of Intradermal Japanese Encephalitis Vaccination (ASTMH 2025) - "Fractional intradermal Imojev® dosing provides effective short-term immunity and maintains seropositivity in most individuals at 1-2 years. However, antibody titres declined substantially, suggesting the need for monitoring and consideration of booster doses to ensure long-term protection, particularly for travellers with ongoing exposure risk or residents in endemic areas. These findings support the use of fractional dosing for short trips (e.g."

CNS Disorders

Antibody responses to Japanese encephalitis virus and dengue virus serotype 2 in children from an orthoflavivirus endemic region after IMOJEV vaccination. (PubMed, PLoS Negl Trop Dis) - "This study shows that IMOJEV vaccination elicited a JEV neutralizing response in 97% of vaccinees and that the magnitude of JEV neutralizing titers post-vaccination was not associated with pre-existing binding antibodies to DENV2. Further, while live JEV vaccination increases DENV2-binding antibodies, this cross-reactivity does not lead to DENV2 enhancement. These findings contribute to a better understanding of the orthoflavivirus antibody response following immunization and the influence of pre-existing heterologous orthoflavivirus antibodies. This could guide vaccination strategies, especially in orthoflavivirus-endemic regions."

Journal • CNS Disorders • Dengue Fever • Infectious Disease

Waning immunity 1-2 years after fractional intradermal Japanese encephalitis vaccination. (PubMed, J Travel Med) - No abstract available

Journal • CNS Disorders

Characterisation of a Japanese Encephalitis virus genotype 4 isolate from the 2022 Australian outbreak. (PubMed, Npj Viruses) - "Herein we conduct a thorough characterization of JEVNSW/22 in three different mouse strains and in human cortical brain organoids (hBOs), and determined the ability of JEVNSW/22 to be neutralized by sera from humans vaccinated with IMOJEV...Overall, our study establishes JEVNSW/22 mouse and hBO models of infection, allowing for possible lethal neuroinvasive infection in mice that was rarer than for other JEV genotypes. JEV vaccination regimens may afford protection against this newly emerged JEV genotype 4 strain, although neutralizing antibody responses are sub-optimal."

Journal • Cerebral Hemorrhage • CNS Disorders • Hematological Disorders • Infectious Disease • IFNAR1 • IRF7

Establishment of a New Endothelial Cell Line of Japanese Eel and Its Application to the Investigation of Temperature Preference of Japanese Eel Endothelial Cells-Infecting Virus. (PubMed, J Fish Dis) - "These results explain the lower mortality of Japanese eels with VECNE at high temperatures. This study will help further understand the infection mechanism of JEECV and develop control measures against it."

Journal • Preclinical • Infectious Disease

Knowledge-based mitigation of the environmental risk of Orthoflavivirus live-attenuated vaccines by targeting viral encoded determinants for the mosquito attenuated phenotype. (PubMed, Vaccine) - "The mosquito-attenuated phenotype also ensures the safety of the licensed LAVs IMOJEV, Dengvaxia and QDENGA...This review discusses knowledge of orthoflaviviral encoded determinants for infection and dissemination in mosquito tissues which have potential utility for the rational design of candidate LAVs. Several attenuating mutations discovered to date are located within genomic regions that are conserved among orthoflaviviruses and can potentially support the establishment of a broadly effective attenuating strategy."

Journal • Review • CNS Disorders • Infectious Disease

Highly Sensitive Duplex Quantitative PCR Assay for Simultaneous Detection of Two Japanese Eel Viruses, Anguillid Herpesvirus 1 and Japanese Eel Endothelial Cells-Infecting Virus. (PubMed, Biology (Basel)) - "Japanese eel endothelial cells-infecting virus (JEECV) and Anguillid herpesvirus 1 (AnHV) are major pathogens in farmed eels...This approach reduces the risk of mass mortality and economic losses in eel farming. This study underscores the critical role of advanced molecular diagnostic technologies in enhancing health management in aquaculture."

Journal • Dermatology • Infectious Disease

A Study to Assess the Safety, Reactogenicity, and Immunogenicity of SK Japanese Encephalitis Messenger Ribonucleic Acid (mRNA) Vaccines (GBP560) in Healthy Adults (clinicaltrials.gov) - P1/2 | N=402 | Recruiting | Sponsor: SK Bioscience Co., Ltd. | Not yet recruiting ➔ Recruiting

Enrollment open • CNS Disorders • Infectious Disease

Long-term immunogenicity of a single-dose live recombinant chimeric Japanese encephalitis vaccine in adults. (PubMed, J Travel Med) - "Imojev® provides durable immunity, with seropositivity exceeding 90% up to 10 years post-vaccination. However, waning immunity in a small proportion of individuals suggests that booster doses may be beneficial for high-risk travellers vaccinated over five years ago."

Journal • CNS Disorders

IMOJEV Live, attenuated chimeric vaccine against Japanese encephalitis: an update after 25 years in use (ASTMH 2024) - "IMOJEV’s product profile, single-dose administration, rapid onset and durable protection, age limits, precautions and contraindications (pregnancy, breastfeeding, immune deficiency) are similar to the highly successful YF 17D vaccine from which it was derived, but with a better safety record. IMOJEV manufacturing in Vero cells is exceptionally robust and could meet unexpected demands resulting from an introduction of JEV into Europe or the Americas."

CNS Disorders • Infectious Disease

A Study to Assess the Safety, Reactogenicity, and Immunogenicity of SK Japanese Encephalitis Messenger Ribonucleic Acid (mRNA) Vaccines (GBP560) in Healthy Adults (clinicaltrials.gov) - P1/2 | N=402 | Not yet recruiting | Sponsor: SK Bioscience Co., Ltd.

New P1/2 trial • CNS Disorders • Infectious Disease

Long-term immunogenicity of the SA14-14-2 Japanese encephalitis (JE) vaccine (CD.JEVAX®) booster following chimeric JE (IMOJEV®) vaccine priming in Thai children. (PubMed, Hum Vaccin Immunother) - "These results indicate that a booster dose of CD.JEVAX® elicits a strong immune response in children previously vaccinated with IMOJEV® while maintaining a good safety profile, thus supporting the interchangeability of these two live-attenuated JE vaccines. Registered at www.thaiclinicaltrials.org (TCTR ID: TCTR20221102003), our study suggests that CD.JEVAX® can be a viable option for booster vaccination in JE prevention programs, potentially enhancing vaccine flexibility and accessibility."

Journal • CNS Disorders

Epidemiology and risk factors of Japanese encephalitis in Taiwan, 2010-2022. (PubMed, PLoS Negl Trop Dis) - "In Taiwan, individuals born before 1976 and those employed in agriculture, forestry, fishing, or animal husbandry had a higher risk of JE. We recommend JE vaccination for people in these high-risk groups who have not been fully vaccinated or have an unknown vaccination history."

Journal • CNS Disorders

An Experimental Medicine Decipher of a Minimum Correlate of Cellular Immunity (clinicaltrials.gov) - P2 | N=70 | Recruiting | Sponsor: Singapore General Hospital | Not yet recruiting ➔ Recruiting

Enrollment open • CNS Disorders • Infectious Disease

FlaviPrime: Flavivirus Cross-priming Potential of IMOJEV (clinicaltrials.gov) - P=N/A | N=18 | Completed | Sponsor: University of Liverpool | Enrolling by invitation ➔ Completed | Trial completion date: Jan 2022 ➔ May 2022

Trial completion • Trial completion date • CNS Disorders

Immunogenicity of a single fractional intradermal dose of Japanese encephalitis live attenuated chimeric vaccine. (PubMed, J Travel Med) - "In healthy adults, a single 0.1 mL ID dose of Imojev was safe and immunogenic, at least in the short-term. Reconstituted vials of Imojev vaccine may not retain their potency after 6 hours. Fractional JE ID vaccination could be a cheaper yet effective alternative for short-term travellers. Further studies need to investigate the immune response in a wider age range of individuals and the long-term immunogenicity of fractional JE ID vaccines."

Journal • CNS Disorders

An Experimental Medicine Decipher of a Minimum Correlate of Cellular Immunity (clinicaltrials.gov) - P2 | N=70 | Not yet recruiting | Sponsor: Singapore General Hospital

New P2 trial • CNS Disorders • Infectious Disease