Risk Factors of Japanese Encephalitis

Residents and travellers to the Torres Strait Islands and areas in South, South-East and East Asia where the Japanese Encephalitis virus is endemic were previously thought to be the only people at risk of Japanese Encephalitis infection. But now, with climate change affecting temperature and rainfall, populations moving from rural to suburban areas, and the increase in Asian travel, the virus is spreading far beyond the known areas (1), and the risk factors of Japanese Encephalitis are evolving as a result. 

Recent Japanese Encephalitis Scare in Australia 

Australian health authorities were put on alert when the first human Japanese encephalitis virus infections emerged in Victoria, Queensland and New South Wales in February 2022, and in South Australia the following month. The Commonwealth Government declared a Communicable Disease Incident of National Significance (2) on March 31, 2022, related to the Japanese Encephalitis virus outbreak, and announced that three people had succumbed to the infection.

Japanese Encephalitis Risk Group

When considering Japanese Encephalitis risk factors, one of the critical elements is older age, from 50 years onwards. This Japanese Encephalitis risk group is thought to have a 10-fold higher probability of symptomatic infection compared to older children and young adults. However, those in the youngest age group (under 10 years) have the highest risk of death or neurologic consequences if they develop symptomatic infection. Japanese Encephalitis infection in the first and second trimester of pregnancy is associated with a risk of miscarriage.

More older people are expected to travel now that international borders are open and vaccination rates are high. And with improved treatments for cancer and chronic diseases, those travelling are more likely to include immunocompromised travellers who carry a higher risk of developing complications from many travel-related infections, including Japanese Encephalitis.

Japanese Encephalitis High-Risk Areas

Japanese encephalitis virus high-risk areas include many parts of Asia, South-East Asia, China and the Indian subcontinent. However, its reservoirs/hosts and vectors have become more widespread, with cases occurring in Indonesia, the Torres Strait Islands, Papua New Guinea, Queensland and now Southern Australia.

Infections are more common in rural, rice-growing areas of Asia, such as the Philippines and Indonesia, where wading birds, pigs, and people live close together. With a move to urbanisation over recent years, infections are occurring in and around some Asian cities. Singapore, Korea and Japan are now in the lower-risk category due to the extensive use of vaccines.

The transmission of the Japanese encephalitis virus also occurs seasonally in the northern areas of China, Siberia, and Nepal, but cases occur year-round in tropical areas like Sri Lanka and the Philippines.

Check the health risks in your chosen destination at Travelvax here.


Holidays and work trips to other countries can be exciting and life-changing – but to ensure your travelling is a positive life change, you need to consider the risks and take care of your health.Travel vaccinations can save you time, money and pain.

At Travelvax, we aim to ensure your health is safe and you come home with great memories of your travels abroad or inside Australia.


How to Get Japanese Encephalitis Vaccine

Vaccines can prevent Japanese encephalitis disease, and they are recommended for people at risk of exposure to the virus. Take the advice of your local health authority in this regard.

Two Japanese Encephalitis vaccines are registered for use in Australia: 

  • Attenuated live viral vaccine 
  • Inactivated virus vaccine

Contraindications: These vaccines should not be given to anyone who has had a severe reaction to them in the past or is known to be hypersensitive to any of the components. The attenuated live viral vaccine is contraindicated for people who are immunocompromised and in pregnant or breastfeeding women. 

At Travelvax, we offer these vaccines to people visiting areas where the Japanese Encephalitis virus is endemic.

Our Travelvax doctors and staff feel privileged to take care of you and your family on your overseas or domestic trip. We provide a service that ranges from vaccinations for Japanese Encephalitis and other diseases and conditions you may acquire overseas or in Australia - to medication and accessories.

To find out more about how we can help you, call one of our dedicated representatives on 1300 360 164 or fill in the convenient online enquiry form. We are happy to answer any questions. Our raison d'être is to ensure you stay safe while overseas.


  1. https://tdtmvjournal.biomedcentral.com/articles/10.1186/s40794-017-0057-x
  2. https://www.health.gov.au/health-alerts/japanese-encephalitis-virus-jev/about
Risk Factors of Japanese Encephalitis