Japanese encephalitis virus (JEV) is transmitted to humans and other animals by the bite of infected mosquitoes. A number of pig properties have recently been identified with JE virus infection. Pigs are important in JEV transmission because pigs develop high levels of viraemia sufficient to infect mosquitoes (amplifying host).


There are two safe and effective vaccines for JE:

  • Imojev: Live attenuated vaccine given by subcutaneous injection. Primary course is one dose. Registered for use in people aged ≥9 months.
  • JEspect: Inactivated Japanese encephalitis vaccine given by intramuscular injection. Primary course is two doses. Available for use in infants and children aged ≥2 months.

For more information, see the Australian Immunisation Handbook.

The Communicable Diseases Network of Australia (CDNA) recommends the following groups should receive the JE vaccine:

  • people who work at, reside at, or have a planned non-deferable visit to a:
    • piggery, including but not limited to farm workers and their families (including children aged 2 months and older) living at the piggery, transport workers, veterinarians (including veterinary students and nurses) and others involved in the care of pigs.
    • pork abattoir or pork rendering plant.
  • personnel who work directly with mosquitoes through their surveillance (field or laboratory based) or control and management, and indirectly through management of vertebrate mosquito-borne disease surveillance systems (e.g. sentinel animals) such as:
    • environmental health officers and workers (urban and remote)
    • entomologists
  • all diagnostic and research laboratory workers who may be exposed to the virus, such as persons working with JEV cultures or mosquitoes with the potential to transmit JEV; as per the Australian Immunisation Handbook.

At this time, it is not recommended that NSW GPs consider JE vaccination for other groups in the community. Mosquito bite avoidance should be encouraged.

Current approach to vaccination in NSW

  • NSW Health has secured a limited supply of JE vaccines.
  • Vaccines are available to order from the State Vaccine Centre strictly for administration to patients in the groups recommended by CDNA. Orders are limited to ten (10) doses per clinic. Please contact your local public health unit for larger orders.

Patient investigation

  • Symptoms of JE include fever and headache, variably accompanied by neck stiffness, disorientation, tremors, coma, convulsions & paralysis. If patients present with symptoms of encephalitis, include JE in your differential diagnosis if they live or have visited rural areas, especially if they were near pig farms or report being bitten by mosquitos.
  • Refer patients with suspected JE to hospital for management and further investigation (as per alert 002/22 issued through the NSW Health Safety Alert Broadcast System).

More information

Further resources and information

Current as at: Monday 28 March 2022
Contact page owner: NSW Health