Questions & Answers
Chickenpox - The Vaccine
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Questions
Answers

Overview

  1. Who recommends this vaccine be given to children and susceptible adults?
    The Centers for Disease Control and Prevention (CDC), the American Academy of Pediatrics (AAP), and the American Academy of Family Physicians (AAFP) have all recommended this vaccine.

  2. When did the chickenpox vaccine become available?
    The chickenpox (varicella) vaccine was licensed for use in Japan and Korea in 1988 and in the United States in 1995.

  3. What kind of vaccine is it?
    The chickenpox (varicella) vaccine is a live attenuated vaccine. This means the live, disease-producing virus was modified, or weakened, in a laboratory to produce a virus that can multiply and produce immunity without causing illness.

  4. Who should get this vaccine?

    Chickenpox vaccine is recommended for the following:

    • All infants (one dose given between 12-18 months of age)
    • All older children who have never had chickenpox (one dose until age 13: for children and adults 13 or older, two doses of vaccine are needed, given 4-8 weeks apart)
    • Adolescents and adults who have never had chickenpox, especially if they are at high risk of exposure to the virus. This includes teachers of young children, day care workers, parents of young children, college students, and others.
    • Non-immune adolescents and adults who live or work with people at high risk for serious complications from chickenpox. This includes health care workers and family contacts of people with compromised immune systems.


  5. Will I ever need any additional doses of chickenpox (varicella) vaccine?
    Booster doses are not currently recommended. But scientists are conducting studies to see if a dose of chickenpox (varicella) vaccine later in life might prevent reactivation of varicella virus, the disease known as zoster or “shingles.”

  6. How safe is this vaccine?
    Millions of doses of chickenpox (varicella) vaccine have been given in the United States, and studies continue to show that the vaccine is safe.

  7. How effective is this vaccine?
    The chickenpox vaccine is very effective. More than 95% of children between 12 months and 12 years of age develop immunity to the disease after one dose of vaccine. For older children and adults, 78% to 82% develop immunity after one dose. And 99% develop immunity after the recommended two doses. Although some vaccinated children will still get chickenpox, they generally will have a much milder form of the disease, with minimal blisters, lower fever, and a more rapid recovery.

  8. Can the vaccine cause chickenpox?
    Because this vaccine is made from a live, but weakened, virus, about 1% of recipients develop a mild form of the disease, consisting of a limited rash, most often with only 5 to 6 blisters. Usually there is no fever. These people are then protected from the more serious, naturally occurring form of the virus.

  9. Can the vaccine cause herpes zoster (shingles)?
    Yes, this is possible but uncommon. The risk from getting shingles from the naturally occurring virus is 4 to 5 times higher than from the vaccine virus. Fewer than 50 cases of shingles in vaccinated people have been reported. All of these cases have been mild and without complications.

Administration

  1. How is this vaccine administered?
    The chickenpox vaccine is given as a shot. A 0.5 ml dose is given subcutaneously.

  2. Should adults be tested before vaccination to see if they are already immune to chickenpox?
    Currently, 90% to 95% of adults are immune to chickenpox because of having had the disease as children. If you know you had chickenpox disease earlier in life, you don't need testing or vaccination, unless you are working in an environment where your immune status must be documented (such as a hospital). If you are uncertain of your medical history, blood testing can be done to see if immunization would be useful.

  3. What side effects have been reported with this vaccine?
    Possible side effects are generally mild and include redness, stiffness, and soreness at the injection site; such localized reactions occur in about 20% of children immunized. A small percentage of people develop a mild rash, usually around the spot where the shot was given.

Contraindications

  1. Who should NOT receive the chickenpox vaccine?
    • Children with weakened immune systems and those with life-threatening allergies to gelatin or the antibiotic neomycin
    • Pregnant women should not receive this vaccine, as the possible effects on fetal development are unknown. Non-pregnant women of childbearing age who have never had the disease may be immunized against chickenpox to avoid contracting the disease while pregnant.

    Sources:

    The Immunization Action Coalition and the Hepatitis B Coalition

    Immunization Healthcare Branch

    Developed in cooperation with the Immunization Action Coalition and the Centers for Disease & Control and Prevention (CDC).