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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 viremia 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 / Ixiaro: Inactivated Japanese encephalitis vaccine given by intramuscular injection. Primary course is two doses. Available for use in infants and children aged ≥2 months, immunocompromised people, and pregnant women.

NSW Health has expanded access to JE vaccine - refer to Information on people recommended to be vaccinated against Japanese encephalitis.

For more information, see the Australian Immunisation Handbook.

Current approach to vaccination in NSW

NSW Health continually reviews the evidence related to JEV risk in NSW in consultation with a range of health and environmental experts. Vaccine doses can be ordered through the State Vaccine Centre. For larger orders that exceed current order restrictions, please contact the local public health unit.

Patient investigation

Symptoms of JE include fever and headache, variably accompanied by neck stiffness, disorientation, tremors, coma, convulsions and 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.

More information

Current as at: Tuesday 28 November 2023
Contact page owner: Communicable Diseases