Questions & Answers
Shingles - The Vaccine
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  1. What kind of vaccine is it?
    Zostavax® is a single-dose, sterile, preservative-free, live, attenuated vaccine manufactured by Merck & Co. Each dose of Zostavax® contains a minimum of 19,400 plaque-forming units (PFU) of the Oka/Merck strain of varicella-zoster virus (VZV) at expiry. The same manufacturing process used for Zostavax® is used to manufacture Varivax®, the vaccine for the prevention of chickenpox, with the exception that Zostavax® contains higher amounts of the attenuated Oka/Merck vaccine virus in order to elicit an appropriate immune response.

  2. Who should get this vaccine?
    Zostavax® or zoster vaccine is a vaccine for shingles, was licensed in 2006, and is indicated for prevention of herpes zoster in people 60 years of age and older.

  3. What side effects have been reported with this vaccine?
    The most common side effects reported in clinical studies include redness, pain, swelling, itching, warmth, and bruising at the injection site, and headaches. In the overall study population, serious adverse events occurred at a similar rate (1.4%) in subjects vaccinated with Zostavax® or placebo.

  4. How effective is this vaccine?

    In the Shingles Prevention Study, half of the participants were assigned a single injection of the zoster vaccine and the other half a placebo vaccine. Neither the researchers nor the participants knew who received vaccine and who received placebo until after the study was over. During an average of more than three years of follow-up, the vaccine reduced the incidence of shingles by 51 percent: 642 cases of shingles occurred among those in the placebo group compared with only 315 in the vaccinated group. Among all vaccine recipients, the total burden of pain and discomfort due to shingles was 61 percent lower than in placebo recipients.

    Zoster vaccine reduced the incidence of shingles by 63.9% in subjects aged 60 - 69 years of age and 37.9% in people aged 70 years or older.

  5. Can the vaccine protect you if you've already been exposed to shingles?
    Yes. According to CDC recommendation if you are 50 years of age or older, you should get one dose of zoster (shingles) vaccine, even if you have had shingles in the past. Some people who have problems with their immune systems or who are taking certain drugs should not get zoster vaccine. Ask your healthcare provider if you should get this vaccine.

  6. 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 5-6 blisters. Usually there is no fever. These people are then protected from the more serious, naturally occurring form of the virus.

  7. Can the vaccine cause shingles?
    Yes. However, a study conducted among children with leukemia determined that after receiving the vaccine these children were much less likely to develop shingles than children who had prior natural chickenpox. Available information from healthy children and adults suggest that shingles is less common in vaccinated healthy people compared with people who have had natural chickenpox.

  8. Should military personnel be tested before vaccination to see if they are already immune to shingles?
    Blood tests can determine whether a person has antibodies to varicella infection, but do not specifically identify if they will get shingles, because the virus can lay dormant for decades.