ADVERSE REACTIONS TO JAPANESE ENCEPHALITIS VACCINE IN TRAVELERS

Vaccination against Japanese Encephalitis (JE) has been carried out ex tensively in many Asian countries for the past 20 years. The vaccine w as generally considered to be effective and of low reactogenity. Howev er, since 1989 an unusual number of systemic reactions characterized m ainly be generalized urticaria and/or angioedema following JE vaccinat ion were reported from Australia, Canada and Denmark. 860 travellers w ere recruited during a period of 16 months for a prospective study wit h the aim to investigate the type and incidence of side effects follow ing JE vaccination (JEV) in German travellers. 826 received a primary immunization (2 injections at days 0 and 7-14) and 34 received a singl e booster injection. A detailed standardized questionnaire were distri buted to all vaccinees after the first injection. A total of 509 quest ionnaires could be evaluated, which represents a return rate of 59.2%. 46% of the vaccinees reported about no adverse events at all. 54% rep orted about one or more adverse effects. Local reactions at the inject ion site were observed by 209 vaccinees, while 65 reported about syste mic side effects like headache, fever, dizziness and generalized rash. There was not significant difference following first or second inject ion of the primary immunization or the booster injection, respectively , regarding incidence, severity or type of side effects. 2.2% of the v accinees reporting reactions sought medical advice and 1.8% were judge d unfit for work for an average of 2.2 days. The amount of systemic re actions might indicate a potential hazard of serious anaphylactic reac tions. Unlike hepatitis A, Japanese encephalitis is an extremely rare disease in travellers. Therefore, the risk of acquiring the disease wh en travelling to affected areas without prior immunization should be c onsidered against the risk of developing serious side effects after va ccination. We conclude that JEV should remain restricted to travellers with an increased risk of acquiring JE.