Japanese Encephalitis
● Back
to Fact SheetsWhat is Japanese
Encephalitis?
Japanese Encephalitis is caused by a mosquito borne virus, and is the
leading cause of viral encephalitis in Asia. Encephalitis means swelling of
the brain from an infection. Some people experience no symptoms while others
develop fever, headache, nausea, vomiting, and weakness. In severe cases,
symptoms include coma, convulsions, paralysis, and possible death. Children
and older adults are at greatest risk but it can affect all ages.
How is Japanese Encephalitis spread?
Japanese Encephalitis is passed to humans through a bite from an infected
mosquito. Swine and certain species of wild birds act as hosts of the virus.
Japanese Encephalitis is supported in areas such as rice fields and
agricultural areas, but it has also been detected in closer to urban centres.
The mosquito generally feeds from dusk through the evening hours. General
mosquito precautions such as wearing long sleeved clothing, using mosquito
nets, and using bug repellent with 30% DEET, are strongly recommended.
Japanese Encephalitis Vaccine
Vaccination against Japanese Encephalitis should be considered for those who
will be living, or travelling for longer than a month in areas where the
virus is endemic.
The vaccine should also be considered for travellers making repeated short
trips to rural areas where the virus is endemic, as well as those travelling
to areas where there is an epidemic.
For children age 3 and older, and adults, 1.0mL of vaccine is administered
in the subcutaneous tissue. Children age 1-3 years receive 0.5mL of vaccine
in the subcutaneous tissue.
Three doses of the vaccine are required to provide immunity:
- First dose now
- Second dose in one week (7 days)
- Third dose 30 days after the first dose
- Booster doses are required every 2 years
For those with time constraints, a fast track schedule is
an option:
- First dose now
- Second dose in one week (7 days)
- Third dose 14 days from the first dose
For both schedules, the last dose should be given at least
10 days prior to travel.
Who should NOT get the Japanese Encephalitis Vaccine?
- Anyone allergic to any component of the vaccine
including thimerosal or rodent proteins
- Anyone with a fever of 38.5 C (101 F)
- Infants under 1 year of age
- Pregnant and breastfeeding women
- Anyone who has had an allergic reaction to this
vaccine in the past
Are there any side effects of the vaccine?
Side effects are rare, however, most reactions occur within 10 days with the
majority occurring within 48 hours. The most common side effects are:
- Redness, soreness, and swelling at the injection site
- Other reactions may include fever, headache, nausea,
vomiting, dizziness, fatigue, joint pain, abdominal pain, and rashes
- Allergic reactions like hives, wheezing, swelling of
the face and mouth are extremely rare, however if this symptoms occur,
seek medical attention immediately and let the Health Unit know about it
It is routine for you to sit and wait in the reception
area for 15 minutes after receiving this vaccine. Please advise the
receptionist immediately if you start to feel ill. |
Leeds,
Grenville and Lanark District Health Unit -
Home Page 