Japanese encephalitis vaccine is a

vaccine A vaccine is a biological Dosage form, preparation that provides active acquired immunity to a particular infectious disease, infectious or cancer, malignant disease. The safety and effectiveness of vaccines has been widely studied and verifie ...

that protects against

Japanese encephalitis Japanese encephalitis (JE) is an infection of the brain caused by the Japanese encephalitis virus (JEV). While most infections result in little or no symptoms, occasional inflammation of the brain occurs. In these cases, symptoms may include he ...

.
The vaccines are more than 90% effective. The duration of protection with the vaccine is not clear but its effectiveness appears to decrease over time. Doses are given either by

injection into a muscle Intramuscular injection, often abbreviated IM, is the injection of a substance into a muscle. In medicine, it is one of several methods for parenteral administration of medications. Intramuscular injection may be preferred because muscles have l ...

or just under the skin. It is recommended as part of routine immunizations in countries where the disease is a problem. One or two doses are given depending on the version of the vaccine. Extra doses are not typically needed in areas where the disease is common. In those with

HIV/AIDS Human immunodeficiency virus infection and acquired immunodeficiency syndrome (HIV/AIDS) is a spectrum of conditions caused by infection with the human immunodeficiency virus (HIV), a retrovirus. Following initial infection an individual ...

or those who are

pregnant Pregnancy is the time during which one or more offspring develops (gestation, gestates) inside a woman, woman's uterus (womb). A multiple birth, multiple pregnancy involves more than one offspring, such as with twins. Pregnancy usually occur ...

inactivated vaccine An inactivated vaccine (or killed vaccine) is a vaccine consisting of virus particles, bacteria, or other pathogens that have been grown in culture and then killed to destroy disease-producing capacity. In contrast, live vaccines use pathogens t ...

should be used. Immunization of travellers who plan to spend time outdoors in areas where the disease is common is recommended. The vaccines are relatively safe. Pain and redness may occur at the site of injection. , 15 different vaccines are available: some are based on

recombinant DNA Recombinant DNA (rDNA) molecules are DNA molecules formed by laboratory methods of genetic recombination (such as molecular cloning) that bring together genetic material from multiple sources, creating sequences that would not otherwise be foun ...

techniques, others weakened virus, and others inactivated virus. The Japanese encephalitis vaccines first became available in the 1930s. It is on the

World Health Organization's List of Essential Medicines The WHO Model List of Essential Medicines (aka Essential Medicines List or EML), published by the World Health Organization (WHO), contains the medications considered to be most effective and safe to meet the most important needs in a health ...

Efficacy

Randomized control trial A randomized controlled trial (or randomized control trial; RCT) is a form of scientific experiment used to control factors not under direct experimental control. Examples of RCTs are clinical trials that compare the effects of drugs, surgical te ...

s on JE-VAX have shown that a two-dose schedule provides protection for one year.

History

Japanese encephalitis vaccines first became available in the 1930s. One of them was an inactivated

mouse brain The mouse brain refers to the brain of Mus musculus. Various brain atlases exist. For reasons of reproducibility, genetically characterized, stable strains like C57BL/6 were chosen to produce high-resolution images and databases. Well known onli ...

-derived vaccine (the Nakayama and/or Beijing-1 strain), made by BIKEN and marketed by

Sanofi Pasteur Sanofi Pasteur is the vaccines division of the French multinational pharmaceutical company Sanofi. Sanofi Pasteur is the largest company in the world devoted entirely to vaccines. It is one of four global producers of the yellow fever vaccine. ...

as JE-VAX, until production ceased in 2005. The other was an inactivated vaccine cultivated on primary hamster kidney cells (the Beijing-3 strain). The Beijing-3 strain was the main variant of the vaccine used in the

People's Republic of China China, officially the People's Republic of China (PRC), is a country in East Asia. It is the world's most populous country, with a population exceeding 1.4 billion, slightly ahead of India. China spans the equivalent of five time zones and ...

from 1968 until 2005. Three second-generation vaccines have entered markets since then: SA14-14-2, IC51 and ChimeriVax-JE. The live-attenuated SA14-14-2 strain was introduced in China in 1988. It is much cheaper than alternative vaccines, and is administered to 20 million Chinese children each year. A purified, formalin-inactivated, wholevirus vaccine known as IC51 (marketed in Australia and New Zealand as JESPECT and elsewhere as IXIARO) was licensed for use in the United States, Australia, and Europe during the spring of 2009. It is based on a SA14-14-2 strain and cultivated in

Vero cell Vero cells are a lineage of cells used in cell cultures. The 'Vero' lineage was isolated from kidney epithelial cells extracted from an African green monkey (''Chlorocebus'' sp.; formerly called ''Cercopithecus aethiops'', this group of monkeys ha ...

s. In September 2012, the Indian firm

Biological E. Limited Biological E Limited (also known as BioE) is an Indian biotechnology and biopharmaceutical company based in Hyderabad, Telangana. It specialises in the areas of low-cost vaccine production. __TOC__ History The company was founded by Dr. D.V.K. ...

launched an inactivated cell culture derived vaccine based on SA 14-14-2 strain which was developed in a technology transfer agreement with

Intercell Intercell AG was a biotechnology company based in Vienna which focused on the development of modern prophylactic and therapeutic vaccines against infectious diseases. The company merged with Vivalis to form Valneva SE in 2012. Intercell was formed ...

and is a

thiomersal Thiomersal (INN), or thimerosal (USAN, JAN), is an organomercury compound. It is a well-established antiseptic and antifungal agent. The pharmaceutical corporation Eli Lilly and Company gave thiomersal the trade name Merthiolate. It has been u ...

-free vaccine. Another vaccine, a live-attenuated recombinant chimeric virus vaccine developed using the

Yellow fever virus Yellow fever is a viral disease of typically short duration. In most cases, symptoms include fever, chills, loss of appetite, nausea, muscle pains – particularly in the back – and headaches. Symptoms typically improve within five days. In ...

known as ChimeriVax-JE (marketed as IMOJEV) was licensed for use in Australia in August 2010 and in Thailand in December 2012.

References

External links

* {{DEFAULTSORT:Japanese Encephalitis Vaccine Inactivated vaccines Vaccines World Health Organization essential medicines (vaccines) Wikipedia medicine articles ready to translate