Questions & Answers
Japanese encephalitis - The Vaccine
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  1. How is JE vaccine administered?

    IXIARO® is an inactivated virus vaccine injected intramuscularly in a two-dose series.  Doses are administered on day zero (the day of initial immunization) and on day twenty-eight.  The IXIARO® series should be completed at least one week prior to potential exposure to JEV.  IXIARO® only comes in 0.5 mL pre-filled syringes.

    1. For children 2 – 35 months of age, a single dose is 0.25 mL and for individuals 3 years of age and older, a single dose is 0.5 mL.
    2. To administer a 0.25 mL dose, expel and discard half of the volume from the 0.5 mL pre-filled syringe by pushing the plunger stopper up to the edge of the red line on the syringe barrel prior to injection.

    A one-time booster dose is recommended for persons 17 years and older if more than one year has passed since completing the primary series and the risk of exposure to the JE virus continues.  Timing of additional booster doses has not yet been determined.  IXIARO® cannot be used as a booster dose for previously administered JE-Vax®.  Previous doses of JE-Vax® are considered void, and the two dose series of IXIARO® should be administered for continued protection against JE.

  2. What are the most common side effects following JE immunizations?

    The most common side effects for children 2 months to one year are injection site redness, fever, irritability, and diarrhea.  The most common side effects for individuals 1 year and older are injection site pain or tenderness, fever, headache, and myalgia. Contact your health care provider if you have any of the following problems because these may be signs of an allergic reaction:

    • difficulty breathing
    • hoarseness or wheezing
    • hives
    • dizziness, weakness or fast heart beat

  3. Are there special restrictions for personnel on flying status?
    Temporary flying restrictions are per Service specific policy.