Japanese Encephalitis
What is it?
Japanese encephalitis is a virus spread by mosquitoes. This virus is related to dengue and yellow fever.
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Although most people who are infected with Japanese encephalitis are asymptomatic, it is still a dangerous disease. The symptoms of Japanese encephalitis are headache, fever, vomiting, seizures, and encephalitis (brain swelling), which can be deadly.
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This vaccine is not recommended as a routine vaccine (in the US), but it may be recommended if you are traveling to a location with Japanese encephalitis.

Areas With Japanese Encephalitis
Map from the World Health Organization
Vaccine Information:
Active Ingredients:
This vaccine uses inactivated Japanese Encephalitis virus as the active ingredient.
Note: there may be trace amounts of DNA and proteins from the cells used to grow the virus for this vaccine.
Inctive Ingredients:
Ingredient amounts based on a 0.5mL dose
Definitions
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Asymptomatic: does not have symptoms or does not appear sick
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Encephalitis: Inflammation (swelling) of the brain
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Seizures: A sudden burst of electrical activity in the brain that can affect movement and behavior
Sources:
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Package insert: https://www.fda.gov/media/75777/download
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General:​
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Aluminum:
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Aluminum Hydroxide: https://medlineplus.gov/druginfo/meds/a601013.html
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Formaldehyde:
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Bovine serum albumin:
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Sodium metabisulfite:
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Protamine Sulfate
Last updated: Feb. 12, 2023