Introduction to JE
JE is a viral disease spread through the bite of infected mosquitoes. It can cause serious neurological complications, including inflammation of the brain (encephalitis), and can lead to death.1,2 There is currently no specific antiviral treatment available for JE, making vaccination one of the most crucial measures for prevention.3,4
The impact of JE
While the development of symptoms is not common in those infected with JE, the consequences for those who do become ill can be devastating. Approximately 100,000 clinical cases of JE occur annually.3
- Up to 30% of individuals who develop JE die.2
- Up to 50% of survivors experience long-term disabilities that can affect their neurological, cognitive, and physical functions.2
These long-term effects, which can include seizures, acute flaccid paralysis, cognitive impairment, and language difficulties, can severely impact a patient's quality of life and place a significant burden on their families and society as a whole.2
The evolving epidemiology of JE
JE risk areas are found in 25 countries across Asia and the Western Pacific. The World Health Organization (WHO) recommends vaccination programmes in all regions where JE poses a significant public health risk.3,5

*Number of travellers from the UK between January 2024 and August 2024.
Adapted from IATA 2024 and Vannice et al 2021.
Adapted from IATA 2024 and Vannice et al 2021.
Recent years have witnessed the spread of JE to new areas, including Australia. In 2022, an unprecedented outbreak in Australia resulted in reported JE cases across five states (New South Wales, Northern Territory, Queensland, South Australia, and Victoria).8 Experts believe that extreme flooding events in the months of February and March in 2021 and 2022 likely contributed to the spread of JE in southern Australia. Flooding can create ideal breeding grounds for mosquitoes and expand the habitat for water birds that can carry the virus over long distances.8

References
- Mansfield, KL, et al. Veterinary Microbiology 2017;201:85–92.
- Centers for Disease Control and Prevention. Japanese encephalitis vaccine: Recommendations of the Advisory Committee on Immunization Practices. MMWR Morb Mortal Wkly Rep 2019;68(2):1–33. Available at: www.cdc.gov. Accessed December 2024.
- World Health Organization. Japanese encephalitis. August 2024. Available at: www.who.int. Accessed December 2024.
- Rogers B, et al. Workplace Health Saf. 2016;64:462-468.
- CDC. Areas at risk for Japanese Encephalitis. June 2024. Available at: www.cdc.gov. Accessed December 2024.
- IATA Global Traveller Insights. August 2024.
- Vannice, KS et al. The future of Japanese encephalitis vaccination: expert recommendations for achieving and maintaining optimal JE control. NPJ Vaccines. 2021;6:82.
- BlueDot’s Initial Assessment. Geographic Expansion of Japanese Encephalitis Virus (JEV) into Australia. September 2022.
Adverse events should be reported.
Reporting forms and information can be found at www.mhra.gov.uk/yellowcard or search for MHRA Yellow Card in the Google Play or Apple App Store. Adverse events should also be reported to the Valneva UK Ltd Medical Information department on Tel: 01506 446608 or via email: safety@valneva.com
Reporting forms and information can be found at www.mhra.gov.uk/yellowcard or search for MHRA Yellow Card in the Google Play or Apple App Store. Adverse events should also be reported to the Valneva UK Ltd Medical Information department on Tel: 01506 446608 or via email: safety@valneva.com