Japanese encephalitis vaccination

Ixiaro®

• Product/vaccine type: inactivated vero cell derived vaccine
• Age: adults and children > 2 months
• Route of administration: intramuscular
• Schedule and duration of protection
  • Primary vaccination consists of 2 doses with an interval of 1 month. For travellers between 18y and 65y, an accelerated schedule can be used with a 7-day interval.
  • Booster vaccines in case of ongoing exposure:
    • first booster dose between 12 and 24 months 
    • in travellers older than 65 years, the firs booster should be given at 12 months
    • a second booster is recommended after 10 years
    • it is unclear if more boosters are needed
  • Children between 2 months and 3 years old should receive half a dose (0.25ml) of the vaccine. There is no specific paediatric vaccine formulation available therefor the standard vaccine is used, with the dose adjusted as appropriate. Instructions for correct preparation and administration can be found in the package leaflet (section 6.6).
  • Ideally, the primary immunization should be completed at least one week prior to potential exposure. 
• Immunogenicity
  • The primary vaccination schedule of 2 vaccine induces an antibody response in more than 95%. 
  • The immunogenicity of the vaccine is lower in adults over 65 years of age seroconversion occurring in approximately 65%.
  • There are no efficacy of effectiveness data for Ixiaro®. The vaccine was licensed based on its ability to induce a serological response. 
  • There are no data on immunogenicity in immunocompromised persons. 

• Side effects
  • The most common side effects are reactions at the injection site and systemic reaction including headache, fatigue, myalgia. These usually occur within the first three days after vaccination, are usually mild and disappear within a few days.
  • Serious adverse events include severe allergic reactions and are extremely rare. 
• Contra-indications
  • History of severe allergic reactions to any of the ingredients
• Co-administration with other vaccines: it may be given at the same time as other live or non-live vaccines.

Other vaccines (not available in Belgium)

In some cases, vaccination at the travel destination can be considered , for example, when travellers do not have enough time to complete the vaccination schedule before departure, or when vaccines are temporarily unavailable in Belgium.
However, it is important to note that travellers will not be optimally protected during the first few weeks of their trip.

The International society of Travel Medicine provides a directory  where you can check whether Japanese encephalitis vaccine are available at the destination.

Imojev®

Imojev® is not available in Belgium but is licensed in Asian countries and Australia (and the vaccine is prequalified by the World Health Organisation. 

• Product/vaccine type: life recombinant (chimeric) vaccine with yellow fever virus strain 17 D backbone
• Age: adults and children > 9 months
• Route of administration: subcutaneous
• Vaccination schedule
  • individuals ≥18 years: a single dose
  • individuals ≥12 months to ≤17 years a booster dose should be given one to two years after the first dose
• Immunogenicity: it induces an antibody response in more than 95% of the vaccinees
• Duration of protection
  • Vaccination induces long term protection. Immunogenicity data up to 5 years after vaccination do not suggest the need for booster doses. There are no data available beyond 5 years. 
  • In mice, it seems to induce protection against lethal yellow fever. [UM2] 
• Side effects
  • reactions at the injection site: pain, induration, redness, swelling
  • systemic reactions: fever, headache, myalgia 
  • serious adverse events like severe allergic reactions are extremely rare 
• Contra-indications
  • pregnancy and breast feeding are contra-indication since there are no safety data available          
  • immune suppression history of severe allergic reactions to any of the ingredients
• Co-administration with other vaccines
  • For administration of other life vaccines an interval of 4 weeks is advised. 
  • Immunogenicity does not appear to be affected by concomitant administration of the measles/mumps/rubella (MMR) vaccine. Concomitant administration can be considered in unavoidable.

CD.JEVAX®

• Product/vaccine type: life attenuated vaccine
• Age: adults and children > 9 months
• Route of administration: subcutaneous
• Schedule and duration of protection
  • primary vaccination consists of a single dose
  • a single booster dose can be given from 3 months to 1 year after the first vaccine to provide long term protection
• Side effects
  • reactions at the injection site: pain, induration, redness, swelling
  • systemic reactions: fever, headache, myalgia 
  • serious adverse events like severe allergic reactions are extremely rare 
• Contra-indications
  • pregnancy and breast feeding are contra-indications
  • immune suppression history of severe allergic reactions to any of the ingredients
• Co-administration with other vaccines
  • Other life vaccines should be administrated with an interval of 4 weeks.