Japanese encephalitis
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Japanese encephalitis is a viral disease. It is the leading cause of viral encephalitis in Asia, with up to 50,000 cases reported each year. The death rate among persons with symptoms of Japanese encephalitis is 30%, with another 30% having serious neurological complications. However, the risk for most travelers is very low, with fewer than 1 case per million travelers. However, rates increase for those staying for prolonged periods in areas where Japanese encephalitis is common.

Japanese encephalitis is transmitted by infected mosquitoes. When an infected mosquito bites a human, the virus is transferred. In addition, wading birds and pigs can be infected and also transfer the virus back to mosquitoes when bitten by a mosquito. Japanese encephalitis transmission occurs mainly in agricultural and rural areas, especially during summer and fall when conditions result in large amounts of standing water.

Most human infections with Japanese encephalitis do not have symptoms. However, a small percentage of those infected develop a sudden fever, headache, and vomiting about 5 to 15 days after infection. These symptoms are followed by mental status changes, neurological changes, weakness, and movement disorders. Seizures are also common, especially among children. There is no specific treatment for Japanese encephalitis. Therapy mainly consists of supportive care and management of complications. The primary public health approaches to JE prevention is through vaccination and the use of other protective measures in at-risk populations.      

About the Vaccine

Currently, there is only one Japanese encephalitis vaccine. It is approved by the FDA for use among persons 2 months of age and older.

Japanese Encephalitis Vaccines Licensed for Use in the U.S.

Product: Ixiaro® (Inactivated Japanese Encephalitis Vaccine)
Manufacturer: Intercell Biomedical
Year licensed: 2009
Product Insert

Indications Contraindications and precautions
  • Travelers spending 1 month or longer in endemic areas (especially rural areas) during the transmission season.
  • Short-term travelers (<1 month) to endemic areas during the transmission season if they plan to travel outside of an urban area and have an increased risk for exposure, such as spending substantial time outdoors in rural or agricultural areas or staying in accommodations without air conditioning, screens, or bed nets.
  • Travelers to an area in which there is an ongoing Japanese encephalitis outbreak.
  • Travelers to endemic areas who are uncertain of specific destinations, activities, or duration of travel.
  • Laboratory workers who may be exposed to Japanese encephalitis virus.
  • People who have had a severe allergic reaction to a previous dose of Japanese encephalitis vaccine or a Japanese encephalitis vaccine component.
  • People who are moderately or severely ill should wait until recovery before receiving any vaccine. Minor illnesses, such as a cold, are not a contraindication.
  • Women who are pregnant.
  • Children younger than 2 months of age. (Ixiaro*).
Vaccine Ages Dose/Route Routine Administration Schedule
Ixiaro 2 months of age and older Dose:
0.25mL (2 months to 3 years of age)
0.5mL (3 years of age and older)

Route: Intramuscular (IM)

* 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.

Routine schedule: 2 doses at 0 and 28 days

Booster dose: Individuals 17 years of age and older who have received a primary immunization series more than 1 year previously may be given a booster dose if ongoing exposure or re-exposure to JEV is expected.
Ixiaro Side Effects
  • Soreness, redness, or swelling where the shot was given (10%).
  • Headache or muscle pain (10%).
  • Nausea, skin rash, fatigue, flu-like illness, or fever (<10%).
  • Severe allergic reaction, sometimes days after the vaccine is given (very rare).       
Product Name Supplied Storage and Handling
Ixiaro
Intercell Biomedical
0.5 mL single dose prefilled syringes (1 per package). Store refrigerated between 2° to 8°C (35° to 46°F). Protect from light at all times. Do not freeze. Discard if vaccine has been frozen.

Ixiaro is a white, cloudy liquid/suspension. Shake well before administering.

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.

Healthcare professionals are invited to join us as we discuss the importance of protecting yourself and others against Japanese Encephalitis. COL Heechoon Lee and Dr. Terry Klein, will provide information on clinical features, ACIP recommendations, and issues/challenges faced by anyone in infected areas. (Recorded on 30 July 2014)
11 Jul 14

Sample Q&A: The Vaccine

Who should not receive the JE vaccines?

People who had a severe allergic reaction to a previous dose of IXIARO® or other JE vaccine, or are allergic to any component of IXIARO®, including protamine sulfate, should not be vaccinated.  IXIARO® contains protamine sulfate, known to cause hypersensitivity reactions in some individuals.

Safety and effectiveness of IXIARO® has not yet been established in pregnant women or nursing mothers.  Pregnant women should generally not receive JE vaccine.  Check with your doctor since it could be recommended under certain circumstances.

If you will be traveling for fewer than 30 days, especially if you will be staying in major urban areas, tell your doctor.  You may be at a lower risk and not need the vaccine.

Recommendations of the Advisory Committee on Immunization Practices, 2013
Recommendations of the Advisory Committee on Immunization Practices (ACIP)
Package Insert - Vaccine
CDC Division of Vector-Borne Infectious Diseases
MMQC-14-1407 06 May 14
Japanese Encephalitis Vaccine (IXIARO) / Update
MMQC-12-1510 21 Aug 12
UPDATE TO MMQC-12-1492 / INTERCELL, INC / JAPANESE ENCEPHALITIS VACCINE / INFORMATION
MMQC-12-1492 08 Aug 12
DEFENSE LOGISTICS AGENCY (DLA) / INTERCELL, INC / JAPANESE ENCEPHALITIS VACCINE / INFORMATION
MMQC-12-1358 07 Jun 12
INTERCELL / JAPANESE ENCEPHALITIS VACCINE / IXIARO / IMPORTANT INFORMATION ON EXPIRY DATING
MMQC-11-1463 07 Jul 11
INTERCELL / JAPANESE ENCEPHALITIS VACCINE (JEV) / IXIARO / MEDICAL INFORMATION
MMQC-11-1447 28 Jun 11
INTERCELL / JAPANESE ENCEPHALITIS VACCINE / IXIARO / IMPORTANT INFORMATION ON EXPIRY DATING
MMQC-11-1332 29 Apr 11
JAPANESE ENCEPHALITIS VIRUS VACCINE (JE-VAX) / SANOFI PASTEUR / DISPOSITION INSTRUCTIONS
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