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Brand Name
Varivax III
Common Name
varicella vaccine
How does this medication work? What will it do for me?

Varicella vaccine is used to prevent infection by the varicella-zoster virus, which causes chickenpox. The vaccine is made up of live virus that has been weakened so that it does not cause infection. The vaccine works by exposing your body to the weakened virus, thus allowing your body to produce its own protection (antibodies) against the disease. The vaccine is recommended for anyone over 12 months old who has not had chickenpox.

This medication may be available under multiple brand names and/or in several different forms. Any specific brand name of this medication may not be available in all of the forms or approved for all of the conditions discussed here. As well, some forms of this medication may not be used for all of the conditions discussed here.

Your doctor may have suggested this medication for conditions other than those listed in these drug information articles. If you have not discussed this with your doctor or are not sure why you are taking this medication, speak to your doctor. Do not stop taking this medication without consulting your doctor.

Do not give this medication to anyone else, even if they have the same symptoms as you do. It can be harmful for people to take this medication if their doctor has not prescribed it.

How should I use this medication?

A qualified health care professional will inject the varicella vaccine under the skin, preferably in the outer, upper arm area.

Adults and adolescents 13 years of age and older receive a dose of 0.5 mL followed by a second 0.5 mL dose 4 to 8 weeks later.

Children 12 months to 12 years of age receive a single dose of 0.5 mL. If a second dose is required, it should be given at least 3 months after the first dose.

Many things can affect the dose of a medication that a person needs, such as body weight, other medical conditions, and other medications. If your doctor has recommended a dose different from the ones listed here, do not change the way that you are taking the medication without consulting your doctor.

It is important to receive this vaccine exactly as prescribed by your doctor.

The vaccine should be stored at a temperature between 2°C and 8°C before it is used. The vaccine can also be stored in the freezer. The vial of the diluent should be stored at room temperature or in the refrigerator. Do not freeze the diluent. After the vaccine has been reconstituted, it should be used within 90 minutes. Protect this medication from light, and keep it out of reach of children.

What form(s) does this medication come in?

Each 0.5 mL dose contains a minimum of 1,350 PFU (plaque forming units) of Oka/Merck varicella. Nonmedicinal ingredients: hydrolyzed gelatin, monosodium L-glutamate, potassium chloride, potassium phosphate monobasic, sodium chloride, sodium phosphate dibasic, sucrose, and urea; residual components of MRC-5 cells including DNA and protein; and trace quantities of neomycin and fetal bovine serum from MRC-5 culture media. This medication does not contain preservatives.

Who should NOT take this medication?

Do not receive this vaccine if you:

  • are allergic to varicella vaccine or any ingredients of this medication
  • are allergic to neomycin or gelatin
  • are pregnant or planning to become pregnant within 3 months of receiving the vaccine
  • are receiving immunosuppressive therapy (e.g., some medications used for the treatment of cancer, radiation therapy, or for transplant recipients)
  • have a family history of congenital or hereditary immunodeficiency
  • have a suppressed immune system (e.g., those with AIDS)
  • have an illness associated with fever
  • have active, untreated tuberculosis
  • have certain blood abnormalities (e.g., leukemia, lymphoma, or any cancer affecting the bone marrow or lymphatic systems)
What side effects are possible with this medication?

Many medications can cause side effects. A side effect is an unwanted response to a medication when it is taken in normal doses. Side effects can be mild or severe, temporary or permanent.

The side effects listed below are not experienced by everyone who takes this medication. If you are concerned about side effects, discuss the risks and benefits of this medication with your doctor.

The following side effects have been reported by at least 1% of people taking this medication. Many of these side effects can be managed, and some may go away on their own over time.

Contact your doctor if you experience these side effects and they are severe or bothersome. Your pharmacist may be able to advise you on managing side effects.

  • abdominal pain
  • chills
  • cough
  • dizziness
  • fatigue
  • fever
  • headache
  • irritability
  • loss of appetite
  • nausea
  • pain, redness, or soreness where vaccine was injected
  • runny or stuffy nose

Although most of the side effects listed below don't happen very often, they could lead to serious problems if you do not check with your doctor or seek medical attention.

Check with your doctor as soon as possible if any of the following side effects occur:

  • fever over 39°C orally (102°F)
  • muscle or joint pain
  • pinpoint red spots on the skin
  • rash similar to chickenpox
  • severe or continuing headache
  • symptoms of lung inflammation (e.g., cough, fever, difficulty breathing)
  • tingling skin
  • trouble breathing
  • unusual bleeding or bruising
  • vomiting

Seek immediate medical attention if any of the following occur:

  • blistering or peeling skin
  • seizures or convulsions
  • signs of a serious allergic reaction:
    • difficulty breathing or swallowing
    • hives
    • itching, especially of the feet or hands
    • reddening of the skin, especially around the ears
    • swelling of the eyes, face, or inside of the nose
    • unusual tiredness or weakness (sudden and severe)
  • signs of stroke (e.g., sudden or severe headache; sudden loss of coordination; vision changes; sudden slurring of speech; or unexplained weakness, numbness, or pain in arm or leg)

Some people may experience side effects other than those listed. Check with your doctor if you notice any symptom that worries you while you are taking this medication.

Are there any other precautions or warnings for this medication?

Before you begin using a medication, be sure to inform your doctor of any medical conditions or allergies you may have, any medications you are taking, whether you are pregnant or breast-feeding, and any other significant facts about your health. These factors may affect how you should use this medication.

NOTE: Vaccination with varicella virus may not result in protection of all healthy, susceptible children, adolescents, and adults.

Duration of protection: It is not known how long the vaccine's protective effects against chickenpox infection will last.

Fever: A doctor may decide to delay this vaccine if the person receiving the vaccine has an acute infection or fever. Mild infections without fever, such as colds, usually do not require delay of the vaccine.

Immune problems: The safety and effectiveness of this vaccine have not been determined for people with immune system problems. It is possible that varicella vaccine may not create enough of an antibody response to protect against infections caused by this virus. Also, this vaccine may not be effective for people receiving immunosuppressive therapy (e.g., some medications used to treat cancer or for transplant recipients).

Medical conditions: Varicella vaccine should not be given for at least 5 months following a blood or plasma transfusion.

Salicylate therapy: People taking the vaccine should not use salicylates (e.g., ASA) for 6 weeks after vaccination, as Reye's syndrome may occur. Children and adolescents should avoid using salicylates unless directed by a doctor.

Transmission: Rarely, healthy people taking the vaccine who develop a varicella-like rash may transmit vaccine virus to healthy susceptible people.

People taking the vaccine should try to avoid, whenever possible, close contact with susceptible high-risk people (e.g., people who are immunocompromised, pregnant people without a history of chickenpox, newborns of people without a history of chickenpox) for up to 6 weeks after receiving the vaccine.

Pregnancy: The safety of varicella vaccine when given during pregnancy has not been determined. Varicella vaccine is not to be used during pregnancy, and pregnancy should be avoided for 3 months after vaccination.

Breast-feeding: It is not known if varicella vaccine passes into breast milk. If you are breast-feeding and taking this vaccine, it may affect your baby. Talk to your doctor about whether you should continue breast-feeding.

Children: The safety and effectiveness of using this medication have not been established for children less than 12 months old. It is not recommended for infants under 12 months old.

What other drugs could interact with this medication?

For a full list of interactions, use the Drug Interaction Checker available on the Drugs.com website.

If you are taking other medications, speak with your doctor or pharmacist. Depending on your specific circumstances, your doctor may want you to:

  • stop taking one of the medications,
  • change one of the medications to another,
  • change how you are taking one or both of the medications, or
  • leave everything as is.

An interaction between two medications does not always mean that you must stop taking one of them. Speak to your doctor about how any drug interactions are being managed or should be managed.

Tell your doctor or prescriber about all prescription, over-the-counter (non-prescription), and herbal medications you are taking. Also tell them about any supplements you take. Since caffeine, alcohol, the nicotine from cigarettes, or street drugs can affect the action of many medications, you should let your prescriber know if you use them.

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