Disease: Japanese encephalitis (JE) is caused by a mosquito-transmitted virus prevalent in parts of South Asia, Southeast Asia, East Asia, and Oceania.
Severity: JE is rare among Canadian travellers but has a high case fatality rate (20-30%) and long-term sequelae (30-50%) among survivors.
Vaccination: IXIARO® is the only JE vaccine authorized in Canada, achieving high seroconversion rates with a two-dose series.
Epidemiology
Transmission: JE virus is transmitted by Culex mosquitoes, primarily in rural agricultural areas with standing water.
Risk: Higher for travellers visiting rural areas, engaging in outdoor activities, or travelling during the rainy season.
Vaccine Preparation Authorized in Canada
IXIARO®: Inactivated, Vero cell culture-derived, adsorbed vaccine.
Immunogenicity and Efficacy
Two-dose Series: Over 95% seroconversion after two doses.
Duration: Protective antibodies decline over time, with booster doses recommended for ongoing risk.
Recommendations for Use
Travellers: Vaccination recommended for individuals 2 months and older at increased risk due to their travel itinerary.
Schedule:
Children (2 months to <3 years): Two 0.25 mL doses.
Individuals (3 years and older): Two 0.5 mL doses.
Accelerated Schedule: Available for adults if needed.
Booster: Recommended 12-24 months after primary series for continued risk.
Safety and Adverse Events
Common Reactions: Injection site pain, tenderness, headache, myalgia, fatigue, fever.
Serious Reactions: Rare occurrences of anaphylaxis.
Special Populations
Pregnancy: Weigh risks of JE exposure against unknown vaccine risks.
Immunocompromised: May receive vaccine, but with potentially lower efficacy.
Related
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