Vaccine Info

Jenvac Japanese Encephalitis Vaccine

Authored by
Last reviewed
October 14, 2022
Fact checked by
Robert Carlson, MD

JENVAC® Vaccine Description 2022

JENVAC® is a single-dose inactivated Japanese Encephalitis (JE) Vaccine. This Vero cell-derived vaccine is prepared from an Indian strain (Kolar- 821564XY) of the JE virus. JENVAC has been developed in collaboration with India's National Institute of Virology. It is a safe and highly effective vaccine that protects against all known strains of Japanese Encephalitis

JENVAC® is a safe and highly effective vaccine that protects against all the known strains of JE.

Bharat Biotech is a pioneering biotechnology company based in India known for its world-class R&D and manufacturing capabilities. 

JENVAC Indication

Japanese Encephalitis is the most important cause of viral encephalitis in Asia. JE is a mosquito-borne flavivirus and belongs to the same genus as dengue, yellow fever, and West Nile viruses. JE is transmitted to humans through bites from infected mosquitoes of the Culex species. Most JE infections are mild (fever and headache) or without apparent symptoms, but approximately 1 in 250 infections result in severe clinical illness. Severe disease is characterized by rapid onset of high fever, headache, neck stiffness, disorientation, coma, seizures, paralysis, and ultimately death.

JE's case-fatality rate can be as high as 30% among those with disease symptoms. Of those who survive, 20%–30% suffer permanent intellectual, behavioral, or neurological sequelae such as paralysis, recurrent seizures, or the inability to speak. There is no antiviral treatment for patients with JE. Treatment is supportive to relieve symptoms and stabilize the patient.


Data from a 2-dose study shows that a single dose of JENVAC is sufficient to elicit the immune response as the subjects who received a single dose were 98.67% sero-protected and the 4-fold sero-conversion was at 93.14% for the ≥1 year to ≤50 years age group.

JENVAC vaccine is administered intramuscularly into the deltoid region of the upper arm for adults and the anterolateral region of the thigh for children. As per the IAP Recommended immunization schedule (2018-19), the JE vaccine should be administered at 12 months and 13 months.

NOTE: Infants younger than 2 months should not be administered JE vaccine; People who have had a life-threatening allergic reaction to the JE vaccine or any ingredient in the vaccine; Have serious allergies of any kind; If the subject is pregnant

JENVAC Adverse Events

The most common adverse events noted were pain, swelling, or redness where the shot was given, headache and muscle aches (mostly in adults), and low fever (mostly in children). Serious side effects from the JE vaccine are very rare.

JENVAC Vaccine News 2022

September 20, 2022 - Science Direct reported on a study that examined Japanese encephalitis virus genotype III from mosquitoes in Tarlac, Philippines.  JEV genotype III was detected in the mosquitoes, culex tritaeniorhynchus. These mosquitoes breed near the rice fields, which are close to human habitation.  Immunization of children is one of the recommended conclusions of this study.

August 1, 2022 - Japanese Encephalitis has claimed four more lives in Assam, India taking the death toll to 52.

May 10, 2022 - Australia reports 38 human cases of Japanese encephalitis this year.

March 4, 2022 - Queensland officials confirmed a human case of JEV in that state. The case had recently traveled in regional parts of the state’s south and is being treated in a Brisbane hospital. The Department of Health is aware of other cases in multiple states of encephalitis of unknown origin that is being investigated for arboviral diseases, including JEV.

Japanese Encephalitis news can be found at Precision 

Clinical Trials

No clinical trials found