Japanese Encephalitis

What is Japanese Encephalitis and How does it spread?

Japanese encephalitis virus (JEV) is a flavivirus related to dengue, yellow fever, and West Nile viruses, and is spread by mosquitoes. There is no cure for the disease. Treatment is focused on relieving severe clinical signs and supporting the patient to overcome the infection. Safe and effective vaccines are available to prevent JE. WHO recommends that JE vaccination be integrated into national immunization schedules in all areas where JE disease is recognized as a public health issue.

What is Japanese Encephalitis Vaccine and Why should Travelers get the vaccine?

Japanese encephalitis vaccine is a vaccine that protects against Japanese encephalitis. The vaccines are more than 90% effective. The duration of protection with the vaccine is not clear but its effectiveness appears to decrease over time. Doses are given either by injection into a muscle or just under the skin. Travelers who go to Asia are at risk of getting Japanese encephalitis. You are at higher risk if you are traveling to rural areas, will be outside frequently, or will be traveling for a long period of time. In mild climates in northern Asia, the risk for JE is greater in the summer and fall. In tropical and subtropical areas, there is a risk year-round.

Who should get the Japanese Encephalitis Vaccine?

Japanese encephalitis vaccine is approved for people 2 months of age and older. It is recommended for travelers to Asia who:
Plan to spend at least a month in areas where JE occurs. Plan to travel for less than a month, but will visit rural areas and spend a lot of time outdoors. Travel to areas where there is a JE outbreak. Laboratory workers at risk for exposure to the JE virus should also be vaccinated. The vaccine is given as a 2-dose series, with the doses spaced 28 days apart. The second dose should be given at least a week before travel. Children younger than 3 years of age get a smaller dose than patients who are 3 or older.

NOTE: The best way to prevent JE is to avoid mosquito bites. Your travel health provider can advise you.

Japanese encephalitis Symptoms

  1. Initial symptoms often include fever, headache, and vomiting.
  2. Mental status changes, neurologic symptoms, weakness, and movement disorders might develop over the next few days.
  3. Seizures are common, especially among children.

What can travelers do to prevent the disease?

  1. Travelers can protect themselves from JE by getting JE vaccine
  2. Cover exposed skin by wearing long-sleeved shirts, long pants, and hats.
  3. Use an appropriate insect repellent as directed.
  4. Stay and sleep in screened or air-conditioned rooms.
  5. Use a bed net if the area where you are sleeping is exposed to the outdoors.