Chiswick Japanese Encephalitis Vaccination

What Is Japanese Encephalitis?

Japanese Encephalitis (JE) is a serious viral infection of the brain, transmitted through the bites of infected mosquitoes — primarily Culex species that breed in rice paddies and feed on birds and pigs. It is the leading cause of viral encephalitis in Asia, with approximately 68,000 clinical cases and up to 20,000 deaths recorded annually across the region.

Most infections cause no symptoms or only mild illness, but in around 1 in 250 cases, the virus causes severe encephalitis (brain inflammation). Of those who develop severe disease, up to 30% die, and many survivors are left with long-term neurological disabilities. There is no specific antiviral treatment — prevention through vaccination is the most effective strategy.

Do I Need the Japanese Encephalitis Vaccine?

Japanese Encephalitis vaccine is recommended for travellers who:

JE risk exists across much of rural and agricultural Asia. The risk is generally low for urban tourists on short stays, but rises considerably with rural exposure and duration of travel.

• Are visiting rural or agricultural areas of Asia, particularly those with rice cultivation or pig farming
• Plan to stay in an endemic country for a month or longer
• Will undertake outdoor activities — cycling, trekking, camping, or fieldwork — in rural areas of Asia
• Are visiting during or shortly after the monsoon season, when transmission rates peak

When Should I Get Vaccinated?

Start the 2-dose course at least 5 weeks before departure — the two doses need 28 days between them, plus a further 7 days after the second dose for protection to develop. If your departure date is sooner than that, contact us — we will advise on whether a partial course offers sufficient benefit for your specific itinerary.

How Many Doses Do I Need?

The Ixiaro vaccine is given as 2 doses: on day 0 and day 28. Both doses are required to achieve adequate protection. A booster dose may be recommended if you are travelling again to endemic areas more than a year after completing your primary course.

Side Effects of the Japanese Encephalitis Vaccine

Ixiaro is well tolerated. The most common side effects are mild pain, redness, or swelling at the injection site, along with headache, muscle aches, and fatigue — all of which typically resolve within a day or two. Serious allergic reactions are very rare. The vaccine can be given alongside most other travel vaccines.