2004-11-02
There is a low incidence of flavivirus infection and hence a low background immunity against flaviviruses in Hong Kong.
The inactivated vaccine (Nakayama strain) is the only Japanese encephalitis (JE) vaccine currently registered in Hong Kong.
Having reviewed the local epidemiology of Japanese encephalitis and the efficacy of available vaccines, the Scientific Committee on Vaccine Preventable Diseases and the Scientific Committee on Vector-borne Diseases have made the following recommendations:
- To give 3 doses of JE vaccines on days 0, 7 and 30 for primary immunization of travellers who plan to stay one month or longer in endemic areas in Asia and Western Pacific Region, particularly the rural areas.
- An abbreviated schedule (days 0, 7 and 14) can be considered when the longer schedule is impractical because of time constraints.
- A two-dose only schedule one week apart should only be considered in rare exceptional cases.
- Booster can be administered between 2-3 years and thereafter every 3 years.
- Vaccinees should be observed for 30 minutes after vaccination and advised to remain in areas with ready access to medical care in the 10 days after receiving a dose of JE vaccine.
Contraindications to Inactivated JE Vaccine
1. Acute infection and fever;
2. Allergic reaction to a previous dose of the vaccine, gelatin, other rodent-derived products, or thimerosal; and
3. History of acute disseminated encephalomyelitis, Guillain-Barre syndrome, multiple sclerosis or other demyelinating diseases.
Special Precautions for the following groups:
1. Pregnancy
2. Immunocompromised
3. Persons with a history of allergic disorders
Scientific Committee on Vaccine Preventable Diseases Scientific Committee on Vector-borne Diseases Letters to Doctors