Japanese Encephalitis Vaccination

Japanese encephalitis is a viral illness found throughout most parts of South and South East Asia.

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Japanese encephalitis is the leading cause of viral encephalitis (inflammation of the brain) in children.

Please note we are unfortunately experiencing stock shortages for Japanese Encephalitis vaccines. Please call your preferred clinic to check stock levels before attending your appointment.  

  • Registered Travel Clinics
    Including Yellow Fever Centres
  • Private clinics with qualified specialists
    Walk-in appointments and online bookings are available
  • Anti-Malarials
    Dispensed on-site in clinic
  • Full range of Vaccines in Stock
    Including Yellow Fever, Typhoid, DTP
  • Same Day appointments
    For last minute travellers
  • CQC registered
    Registered and regulated by the Care Quality Commission


The virus is transmitted by the bite of a mosquito, which feeds from dusk until dawn. Pigs and water birds act as sources of the virus. Thus, the infection is mainly found in rural and semi-rural areas. Transmission can vary by season in individual countries, with highest risk during rainy season. However, other countries have year round transmission.


Approximately 1 in 250 people became unwell after infection. Children and older adults are at higher risk of developing symptoms.

Symptoms include high fever, convulsions, headache and neck stiffness.

Up to 30% of cases are fatal and 30-50% of individuals who develop encephalitis have permanent neurological disability.


There is no specific treatment for Japanese Encephalitis, only supportive care.


The infection can be prevented by vaccination and mosquito bite prevention measures, such as effective insect repellent and mosquito nets.

There is currently only one licensed vaccine against Japanese encephalitis in the UK. It is an inactivated vaccine and cannot cause the disease n the vaccinated individual and nor is the vaccinated individual infectious to others.


The vaccine can be given to individuals aged 2 months and above who are travelling to or going to live in risk areas for Japanese Encephalitis.

Age range Vaccine Brand Dose Method of Administration Number of doses primary course Interval between doses primary course First Booster dose requirements Second Booster dose requirements
2 months-3 years of age Ixiaro 0.25ml Intramuscular injection to the thigh or deltoid muscle. 2 doses 2nd dose administered 28 days after 1st dose If at ongoing risk for infection (such as travelling to live in endemic country)-First Booster at 12 months

All other Travellers-First Booster at 12-24 months
Children over 3 years up until 18 years Ixiaro 0.5ml Intramuscular injection to the deltoid muscle 2 doses 2nd dose administered 28 days after 1st dose If at ongoing risk for infection (such as travelling to live in endemic country)-First Booster at 12 months

All other Travellers-First Booster at 12-24 months
Adults 18 years-65 years Ixiaro 0.5ml Intramuscular injection to the deltoid muscle 2 doses Standard Schedule=2 doses given at day 0 and day 28

Rapid Schedule-2 doses at day 0 and day 7
If at ongoing risk for infection (such as travelling to live in endemic country)-First Booster at 12 months

All other Travellers-First Booster at 12-24 months
Second Booster at 10 years if at risk.

The rapid schedule can be used if there is insufficient time to complete the standard schedule.

Adults between 18-65 years-rapid course of 2 doses Ixiaro given at day 0 and second dose 7 days later. This schedule provides the equivalent protection 7 days after the second dose as the standard schedule.

Additionally, the DOH guidance advises that clinical staff can adopt this ACCELERATED schedule “off license” in children aged 12-17 yrs also, if there is insufficient time before departing for their trip.


The vaccine cannot be given to:

  • Infants under 2 months of age
  • Individuals with a history of severe allergic reaction to previous dose of the vaccine or any  of it’s components.
  • Acute illness with high fever (greater than 38.5 degrees Celsius)


There is insufficient data of the effects of the vaccine during pregnancy and therefore, it should not be administered to pregnant women.

Breast Feeding

Vaccination during breast feeding should be avoided due to lack of safety data.

Common Side Effects

Local injection site reactions including redness, swelling and pain.

Other side effects include fever, “flu-like” illness, muscle aches.

Interactions with Other Vaccines

The Japanese Encephalitis vaccine can be given at the same time as other vaccines including:

  • Hepatitis A
  • Hepatitis B
  • Rabies
  • Yellow fever
  • Typhoid
  • MMR
  • Chicken Pox
  • All childhood vaccines

1) How long does take for the vaccine to become effective?

The vaccine is effective 7 days after the second dose has been received.

2) What does the vaccine contain?

The vaccine contains the following ingredients:

  • Phosphate buffered saline consisting of:
  • Sodium chloride
  • Potassium dihydrogen phosphate
  • Disodium hydrogen phosphate
  • Water for injections
  • aluminium hydroxide

The vaccine does not contain the following:

  • Latex
  • Gelatin
  • Thiomersal
  • Egg

3) If I had a different brand of Japanese encephalitis, do I need to restart the course?

Previously, Green Cross vaccine was available in the UK, which consisted of a three dose course. The Department of Health advises that adults who have had a previous course of any Japanese encephalitis vaccine can receive a single dose of IXIARO® as a booster.

4) If I travel regularly to risk areas , would I need further booster?

The advice on long term protection and further boosters in adults is not known currently. The vaccine manufacturers have advised the following in their product description:

“Long-term seroprotection data following a first booster dose administered 12 – 24 months after primary immunization suggest that a second booster should be given 10 years after the first booster dose, prior to potential exposure to JEV”. (SPC Ixiaro)

However, we would need to wait for the advice from the UK’s Joint Committee on Vaccinations and Immunisations for confirmation of this.

5) What about boosters in children?

The Department of Health advises that if children under 18 years are at continued risk of infection, then a booster dose can be considered.

6) Can the vaccine be given to infants under 2 years of age?

The vaccine cannot be given infants under 2 months of age, as there is no data on safety or effectiveness  in this age group.

7) How effective is one dose of the Japanese Encephalitis vaccine?

Clinical studies show that one dose of the Japanese encephalitis vaccine provides around 21% protection 10 days after receiving the first dose and around  40% protection 28 days after the first dose. 

Therefore, if there is not enough time to complete the 2 dose course, additional insect bite prevention measures are vital in protecting against contracting the infection.

8) Can the second dose be given later than 28 days?

The second dose of Japanese encephalitis vaccine can be given up to 11 months after the 1st dose and still provide an effective immune response. 

Travel Vaccinations

Whether you are going on a honeymoon, trekking or going on a last minute business trip, we can provide you with a comprehensive travel clinic service. Our specialist nurses and pharmacists offer vaccinations for travel to any country in the world, as well as destination specific health advice tailored to your itineraries. Click here for a full list of vaccinations we offer. Please note: Parents or legal guardians will need to directly accompany any child who is being vaccinated and bring along a photo ID for themselves.


Pre-Travel Advice

Our pre-travel consultations are with experienced travel health specialists and pharmacists who will assess the impact of any pre-existing medical conditions along with your vaccine requirements. They will discuss in detail countries at risk, precautions you can take to avoid exposure and how to travel safely. We also highly recommend visiting the government websites which has the latest travel news and advice for every destination.

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