Japanese Encephalitis Vaccine: Schedule and Precautions

Indications

Prevention of Japanese encephalitis in children from 1 year and adults in endemic countries, and in travellers spending more than 1 month in endemic rural areas during the wet season.

Composition, forms, route of administration

• Inactivated virus vaccine.
• Powder for injection in single-dose vial, to be dissolved with the entire vial of diluent supplied by the manufacturer, for SC injection.

Dose

There are several vaccination schedules. For travellers, a common schedule is 3 doses on D0, D7, and D28, with a booster every 3 years if risk persists.

• Child from 1 to 3 years: 0.5 ml per dose.
• Child over 3 years and adult: 1 ml per dose.
• An accelerated schedule of D0, D7, and D14 is possible but is likely to result in lower antibody levels than the standard schedule.
• The third dose should be given at least 10 days before departure to ensure adequate immune response and access to medical care in the event of adverse reactions.

Contra-indications, adverse effects, precautions

• Do not administer to patients with history of allergic reaction to a previous injection of Japanese encephalitis vaccine.
• Vaccination should be postponed in the event of severe acute febrile illness; minor infections are not contra-indications.
• May cause redness and swelling at the injection site, fever, headache, chills, asthenia, hypersensitivity reactions, and rarely encephalitis or encephalopathy.
• Do not mix with other vaccines in the same syringe.
• If administered simultaneously with EPI vaccines, use different syringes and injection sites.
• Pregnancy: only administer if there is a high risk of contamination.
• Breast-feeding: no contra-indication.
• Protection lasts at least 2 years after 3 doses.
• Different JE vaccines may have different dosages and administration schedules. For each vaccine, follow manufacturer's instructions.