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