Japanese Encephalitis (JE) is a mosquito-borne viral disease common in parts of Asia. Hypersensitivity reactions may occur in patients receiving a vaccine against the virus. Certain risk factors can help identify persons more likely to have an allergic reaction.


Types of hypersensitivity reactions:

(1) common: urticaria and/or angioedema

(2) uncommon: anaphylaxis, Guillain-Barre syndrome


Risk factors for an adverse reaction to JE vaccine:

(1) female gender

(2) age < 30 years of age

(3) history of allergic reactions: urticaria, history of allergic skin reactions, nickel sensitivity, hayfever, allergic rhinitis


Contraindications to use of the JE vaccine because of potential reactions

(4) history of allergy to one of the components of the vaccine, including neural or rodent proteins, thiomerosal, gelatin

(5) history of prior reaction to the vaccine


Patients receiving the vaccine should have the final (third) dose given 8 or more days prior to departure. In the event that a hypersensitivity reaction should develop, this allows sufficient time for therapy prior to the starting the trip.


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