Plesner A, Ronne T, Wachmann H
          Department of Epidemiology, Statens Serum Institut, Copenhagen, Denmark.
          [email protected]
          Vaccine 2000 Mar 6;18(17):1830-6

        Japanese encephalitis (JE) vaccine is widely used in Asia for childhood
        immunizations, but the vaccine is also used for travellers to Asia from
        other parts of the world. In Denmark, more than 400,000 doses have been
        distributed from Statens Serum Institut since 1982. In 1989, the first
        allergic mucocutaneous reactions after JE vaccination were registered in
        Denmark and, although the number of reactions have decreased since 1992,
        reactions are still observed. No explanation of these reactions have
        been found. The present case-control study, including 49 travellers with
        allergic reactions and 148 travellers without similar reactions after JE
        vaccination was performed in order to clarify any possible risk factors.
        About one third of the adverse reactions to the vaccine could be
        attributed to an allergic predisposition in the vaccinees. The main risk
        factors were young age, female gender and previous allergic skin
        reactions or hayfever. The study also indicated that cases more often
        reacted to nickel and more often had severe edema after mosquito or
        other insect bites. Hormone intake was more often spontaneously reported
        by females in the case group. Accordingly, information on any history of
        allergy in young adults should be given before JE vaccination, the
        vaccination should be carried out more than a week before departure and
        antihistamine treatment should be available if a reaction occurs.