Description and Brand Names

Drug information provided by: Micromedex

US Brand Name

  1. Ixiaro


Japanese encephalitis virus vaccine, inactivated adsorbed (IXIARO®) is used to prevent infection caused by the Japanese encephalitis virus. It works by causing your body to produce its own protection (antibodies) against the virus.

Japanese encephalitis is caused by the bite of a mosquito that lives in certain parts of Asia. It is a serious infection that can cause flu-like symptoms (eg, fever, chills, tiredness, headache, nausea, and vomiting), confusion, agitation, brain damage, and possibly death. This vaccine does not protect against encephalitis caused by other viruses.

This vaccine is only available from your doctor or other authorized health care professional.

This product is available in the following dosage forms:

  • Suspension

Before Using

In deciding to use a vaccine, the risks of taking the vaccine must be weighed against the good it will do. This is a decision you and your doctor will make. For this vaccine, the following should be considered:


Tell your doctor if you have ever had any unusual or allergic reaction to this medicine or any other medicines. Also tell your health care professional if you have any other types of allergies, such as to foods, dyes, preservatives, or animals. For non-prescription products, read the label or package ingredients carefully.


Appropriate studies have not been performed on the relationship of age to the effects of Japanese encephalitis virus vaccine, inactivated adsorbed in children younger than 2 months of age. Safety and efficacy have not been established.


Appropriate studies performed to date have not demonstrated geriatric-specific problems that would limit the usefulness of Japanese encephalitis virus vaccine, inactivated adsorbed in the elderly.


Information about this japanese-encephalitis-virus-vaccine-inactivated-adsorbed-intramuscular-route
Pregnancy Category Explanation
All Trimesters B Animal studies have revealed no evidence of harm to the fetus, however, there are no adequate studies in pregnant women OR animal studies have shown an adverse effect, but adequate studies in pregnant women have failed to demonstrate a risk to the fetus.


There are no adequate studies in women for determining infant risk when using this medication during breastfeeding. Weigh the potential benefits against the potential risks before taking this medication while breastfeeding.

Drug Interactions

Although certain medicines should not be used together at all, in other cases two different medicines may be used together even if an interaction might occur. In these cases, your doctor may want to change the dose, or other precautions may be necessary. Tell your healthcare professional if you are taking any other prescription or nonprescription (over-the-counter [OTC]) medicine.

Other Interactions

Certain medicines should not be used at or around the time of eating food or eating certain types of food since interactions may occur. Using alcohol or tobacco with certain medicines may also cause interactions to occur. Discuss with your healthcare professional the use of your medicine with food, alcohol, or tobacco.

Other Medical Problems

The presence of other medical problems may affect the use of this vaccine. Make sure you tell your doctor if you have any other medical problems, especially:

  • Allergy to protamine sulfate, history of—Should not be used in patients with this condition.
  • Bleeding problems or
  • Thrombocytopenia (low blood platelet count)—May cause side effects to become worse.
  • High fever (more than 100°F) or
  • Infection—The symptoms of the condition may be confused with the possible side effects of the vaccine.
  • Immune deficiency or
  • Immune system problem—May not work properly in patients with these conditions and may cause side effects to become worse.

Proper Use

A nurse or other trained health professional will give you this vaccine. This vaccine is given as a shot into the muscle of your upper arm (in adults and children 3 years of age and older) or thighs (in children up to 3 years of age).

This vaccine is given in 2 doses. Dose 2 is scheduled 28 days after Dose 1. It is very important that you receive both doses of the vaccine at least 7 days before you plan to travel out of the country. If you miss the second shot, call your doctor to make another appointment as soon as possible.

If you have received the second dose of the vaccine series more than 1 year ago, consult first with your doctor. A booster dose may be given before you plan to travel out of the country.

This vaccine comes with a patient information sheet. It is very important that you read and understand this information. Be sure to ask your doctor about anything you do not understand.


It is very important that you return to your doctor at the right time for the second dose. Be sure to tell your doctor about any side effects that occur after you receive this vaccine.

You should receive both vaccines of the 2 vaccine series 1 week before traveling to an area where you will be exposed to the Japanese encephalitis virus.

This vaccine may cause serious allergic reactions, including anaphylaxis. Anaphylaxis can be life-threatening and requires immediate medical attention. Tell your doctor right away if you have a rash, itching, fast heartbeat, trouble breathing, trouble swallowing, or any swelling of your hands, face, or mouth after receiving the vaccine.

Since the vaccine may not protect everyone completely, it is very important that you use precautions to reduce your chance of mosquito bites. These include using insect repellents and mosquito nets, wearing protective clothing, and staying indoors during twilight and after dark.

Side Effects

Along with its needed effects, a medicine may cause some unwanted effects. Although not all of these side effects may occur, if they do occur they may need medical attention.

Check with your doctor or nurse immediately if any of the following side effects occur:

More common

  1. Chills
  2. cough
  3. diarrhea
  4. fever
  5. general feeling of discomfort or illness
  6. headache
  7. joint pain
  8. loss of appetite
  9. muscle aches and pains
  10. nausea
  11. runny nose
  12. shivering
  13. sore throat
  14. sweating
  15. trouble sleeping
  16. unusual tiredness or weakness
  17. vomiting

Less common

  1. Body aches or pain
  2. difficulty with breathing
  3. ear congestion
  4. loss of voice
  5. nasal congestion
  6. sneezing

Incidence not known

  1. Burning, crawling, itching, numbness, prickling, "pins and needles", or tingling feelings
  2. numbness or tingling of the hands, feet, or face

Some side effects may occur that usually do not need medical attention. These side effects may go away during treatment as your body adjusts to the medicine. Also, your health care professional may be able to tell you about ways to prevent or reduce some of these side effects. Check with your health care professional if any of the following side effects continue or are bothersome or if you have any questions about them:

More common

  1. Difficulty with moving
  2. joint pain
  3. muscle cramps or stiffness
  4. swollen joints

Less common

  1. Back pain
  2. pain, itching, redness, or swelling where the shot was given
  3. rash

Other side effects not listed may also occur in some patients. If you notice any other effects, check with your healthcare professional.

Call your doctor for medical advice about side effects. You may report side effects to the FDA at 1-800-FDA-1088.