Japanese Encephalitis
日本腦炎疫苗
A travel vaccine for specific itineraries — rural Asia in summer, long stays, outdoor exposure. Not routine for most HK travellers.
Ixiaro
What is it?
Japanese encephalitis vaccines prevent Japanese encephalitis and are considered according to itinerary and exposure risk. Travel Health Service describes inactivated and live attenuated types; the Ixiaro schedule below is product-specific and does not apply to every JE vaccine.
Japanese encephalitis (JE) is a viral brain infection spread by mosquitoes, mainly Culex species that breed in rice paddies and pig farms. It is the leading cause of viral encephalitis across Asia.
Around 1 in 250 infected people develop encephalitis — roughly 30% die and many survivors have lasting neurological damage.
Hong Kong guidance, eligibility and individual assessment
Discuss JE vaccination with a travel-health clinician for prolonged rural stays, significant outdoor exposure or outbreak-area travel in endemic regions. Assessment depends on the destination, season, activities and length of stay.
- Spend a month or longer in rural areas of endemic countries during transmission season
- Travel for shorter periods but with significant outdoor or rural exposure
- Travel to areas with active JE outbreaks
Routine short urban tourism does not usually require JE vaccination, but assess the actual itinerary. THS recommends booking a consultation at least eight weeks before travel; consultation lead time is separate from dose intervals and time to protection.
International reference (US CDC)
US CDC recommendation broadly aligned: JE vaccine for travellers spending a month or more in endemic areas, or shorter stays with high outdoor exposure during transmission season.
Schedule
Adults (Ixiaro): 2 doses, 28 days apart. Accelerated schedule (0, 7 days) is approved for adults 18-65 if time is tight.
Children (Ixiaro): approved from 2 months of age. Same 2-dose schedule, paediatric dose.
Aim to complete the course at least 1 week before travel.
Vaccine product reference
| Brand | Manufacturer |
|---|---|
| Ixiaro · Inactivated, Vero cell-derived JE vaccine | Valneva |
These product names are reference examples, not a complete list of registered products or confirmation of current supply. Confirm the exact product and availability with the provider.
Side effects
Common reactions include injection-site pain, headache, muscle aches, mild fever and tiredness. Ask the clinician about expected reactions for the selected product and when to seek care.
Common myths
Myth: I'm going to Asia for a holiday — I need every travel vaccine.
Reality: JE is for specific itineraries — rural, outdoor, long stays, transmission season. A 1-week city trip usually doesn't need it. Talk to a travel health clinic about your specific plan.
Cost and vaccination locations
Book a consultation with a Department of Health Travel Health Centre to check JE assessment and vaccination services. THS recommends booking at least eight weeks before departure, subject to confirmation. Ask separately about fees and the exact product.
You may also enquire with a private travel-medicine or GP clinic, confirming whether it provides the service, the vaccine, stock, applicable schedule and total fee; do not assume every clinic stocks it.
Sources
- Travel Health Service: Japanese encephalitis vaccine · Travel Health Service, DH (HK)Source checked:
- Travel Health Service: centres and consultation booking · Travel Health Service, DH (HK)Source checked:
The review type is not recorded; this does not establish clinical review. Source checks are dated below. How sources are used
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