Japanese Encephalitis

Japanese encephalitis is a viral infection spread by mosquitoes in parts of Asia and the Western Pacific. Most infections are mild, but in rare cases it can cause severe brain inflammation, which may be life-threatening or lead to long-term complications.

Once the course is complete, protection lasts for at least 1–2 years. A booster may be recommended for ongoing risk.

The vaccine is given as two doses, usually spaced 28 days apart. For those needing rapid protection, an accelerated schedule may sometimes be used.

The vaccine is often recommended for travellers spending extended periods in rural or agricultural areas where the virus is present, particularly during the rainy season. It may also be considered for those making shorter trips if activities or destinations put them at higher risk.

We recommend seeking travel health advice first. You can book a consultation with our travel nurse here .

Most people tolerate the vaccine well. The most common side effects are soreness at the injection site, mild fever, or headache. These usually settle within a day or two. Serious side effects are very rare.