Japanese Encephalitis vaccine

About Japanese Encephalitis(JE) disease

Japanese encephalitis is a disease which is spread by mosquitoes. Pigs and water fowl can also transmit this dangerous infection. This disease can occur throughout the year with a peak in the rainy season. It usually strikes at children but may sometimes affect adults too.  Epidemics of JE have often struck South-east Asian countries like Japan, South Korea, and China. Some rural pockets of India (West Bengal, Bihar, Andhra Pradesh (AP) and North Eastern States) have reported sporadic outbreaks.  1

Some common symptoms of Japanese encephalitis are

Why is a vaccine required?

Japanese encephalitis (JE) is one of the most dangerous mosquito-spread diseases. Many areas in the North-East belt of India have experienced recurrent bouts of this treacherous infection. If one resides in these areas or is planning to travel to them or to South Asian countries, getting vaccinated may help. Prevention of JE is vital as currently, there is no specific agent medication available against JE. Moreover, more than 20% to 30% of JE cases are fatal, and 30–50% result in permanent disability. 4 So one should not take chances if planning to visit South-Asian countries and other JE-prone areas, and should get vaccinated.

Who should get the vaccine? 5

What is the schedule for Japanese encephalitis vaccine?  5

There are three types of JE vaccines. Each of them has a different schedule. The doctor is the best judge of which vaccine is most suitable depending upon the age of the child and the place of residence.

Live attenuated: A two dose schedule, first dose at 9 months along with measles vaccine and second at 16 to 18 months along with DTP booster, minimum age: 8 months

 Inactivated: For children aged ?1 to ?3 years -2 doses each administered intramuscularly on days 0 and 28, minimum age: 1 year

Inactivated Vero cell culture-derived Kolar strain : 2 doses administered intramuscularly at 4 weeks interval, minimum age: 1 year

Catch-up vaccination:

If one misses out on a vaccine dose, the chances of falling prey to this infection during an outbreak goes up. Since JE does not have a specific cure; it is necessary to get your vaccination in order with a catch-up vaccination.  Catch up vaccination is essential for all susceptible children up to 18 years during disease outbreak.5

How effective is the vaccine?

Since Japanese encephalitis has no specific cure and all cases need supportive and symptomatic treatment in hospital, prevention is vital. Studies have validated the efficacy of these vaccines in JE prevention. 6

Does it have any side effects?

Some patients may experience pain and redness at the site of injection. Side-effects like headache, fever, dizziness and generalized rash may be experienced in some cases.7

 References:

  1. Indian J Med Res. 2015 Dec; 142(Suppl 1): S30–S32.
  2. J Microbiol Immunol Infect. 2009 Aug;42(4):296-302.
  3. Hong Kong Med J. 2005 Jun;11(3):182-8.
  4. Biomed Res Int. 2013; 2013: 152656.
  5. http://acvip.org/files/IAP-immunization-schedule-2016-IP-2016-Epub.pdf
  6. Vaccine. 2006 Mar 24;24(14):2669-73. Epub 2005 Nov 10.
  7. J Infect. 1996 Mar;32(2):119-22.