Japanese Encephalitis Virus | JV Vaccine Type | Usage | Precautions | Side Effects

Japanese Encephalitis Virus | JV Vaccine Type | Usage | Precautions | Side Effects

  • Japanese Encephalitis (JE) is caused by Japanese Encephalitis virus (JEV), an RNA virus of Flaviviridae family.
  • JEV is an important cause of encephalitis in Asia, especially the countries in East Asia like China, India, Republic of Korea, Sri Lanka and Thailand.
  • JE virus is transmitted to humans by the bite of mosquitos of the Culex genus.

Vaccine Type


  • Recombinant protien vaccine

Available as


  • Live-attenuated (SA 14-14-2 strain): This vaccine is widely used in Asian region including China, India etc.
  • Inactivated, Vero cell derived (SA 14-14-2 strain): This vaccine has been licensed for use in US, Australia and European countries.
  • Inactivated Vero cell-derived vaccines (Beijing-1 strain): It has been licensed for use in Japan.
  • Live chimeric vaccine (with yellow fever 17D as backbone): It has been approved for use in Australia and Thailand.

Effectiveness


  • JV vaccine is considered about 90-95% effective in preventing new cases of JE in children.

Usage


  • Routine vaccination of all children is carried out in some countries of East Asia. Travelers to JE-endemic areas are also recommended to receive vaccination before departure.
  • Live-attenuated (SA 14-14-2 strain): First dose is given at 8 months age followed by a booster dose at 2 years of age. In some countries an additional booster dose is given at 6-7 years age. In some others, only a single dose with no booster(s) is considered enough.
  • Inactivated, Vero cell derived (SA 14-14-2 strain): Two IM doses given 4 weeks apart, followed by a booster after 1 year.
  • Inactivated Vero cell-derived vaccines (Beijing-1 strain): Primary immunization consists of three doses at 0, 2, 27 days, followed by a booster dose 12-14 months later. A booster dose every 3 years thereafter is recommended.
  • Live chimeric vaccine (with yellow fever 17D antigen): A single dose is recommended. Data regarding the need and timing of booster dose is insufficient currently.

Precautions


  • People who had severe allergic reaction to a previous dose of the vaccine, or who are allergic to any component of the vaccine are contraindicated to receive the vaccine.
  • Live-attenuated vaccines should be avoided in pregnancy unless there is a high risk of infection.
  • Some acutely ill patients may be advised to delay vaccination unless they are well again.