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Vaccine Information

Entry last updated: 12/12/2006

- Understanding the Disease
- Available Vaccines
- History of the Vaccine
- Who Should and Should Not Receive the Vaccine
- Dose Schedule
- Effectiveness of the Vaccine
- Known Side Effects
- Related Issues
- Key References and Sources of Additional Information

Understanding the Disease

Zoster (shingles) is an infection caused by the varicella-zoster virus (VZV), the cause of chickenpox. The VZV virus—which remains in the nerve cells for life after chickenpox or after the chickenpox vaccine [Link]—may reappear as shingles in later life, particularly in the elderly and those who are immunocompromised. This is because of declining immunity to the VZV virus over time. Thus, anyone who has had chicken pox or the chickenpox live virus vaccine is at risk for developing shingles. While shingles can occur at any age, the risk increases as people get older. When shingles develop, a rash or blisters appear on the skin, generally on one side of the body. The skin blisters in shingles contain the VZV virus so chickenpox-susceptible children can develop chickenpox when exposed to shingles.

Because the infection in shingles starts in the nerves, shingles can also be painful. Pain can last for months after the rash has healed and can be very severe—this is called post herpetic neuralgia or PHN. Shingles occurs most commonly in older individuals and PHN is a more common complication of shingles in older individuals.

Available Vaccines

Product: Zostavax
Manufacturer: Merck
Year licensed: 2006

Note: Reconstituted Zostavax must be discarded if not used within 30 minutes. CDC recommends storage of this and all live virus vaccines (MMR, MMRV and varicella) in the freezer at 5o F or below.

This vaccine does not contain thimerosal. For information on the thimerosal content in vaccines, see the Food and Drug Administration at

History of the Vaccine

A varicella vaccine developed in Japan in the 1970’s was licensed for routine use in Japan and Korea in 1988. The varicella vaccine was recommended for routine use in the United States in 1995. Zostavax is very similar to varicella vaccine but contains a higher dose of the vaccine virus. In 2006, Zostavax was licensed and recommended for routine administration to adults over the age of 60 years.

Who Should and Should Not Receive this Vaccine

Who should receive the vaccine?

  • Individuals 60 years of age and older

Who should not receive the vaccine?

  • Children should not receive Zostavax; it is not a substitute for varicella vaccine (Varivax).
  • People who have had a life-threatening allergic reaction to gelatin, to the antibiotic neomycin, or to a previous dose of the chickenpox vaccine. 
  • Persons with primary or acquired immunodeficiency states including leukemia, lymphoma of any type, other malignant neoplasm affecting the bone marrow or lymphatic system or AIDS or other clinical manifestations of infection with human immunodeficiency viruses.
  • Persons who are taking immunosuppressive therapy, including high-dose corticosteroids.
  • Persons with active untreated tuberculosis.
  • Women who are or may be pregnant.

This vaccine is recommended by:

  • Advisory Committee on Immunization Practices of the Centers for Disease Control and Prevention
  • American Academy of Family Physicians

The summary of adolescent/adult immunization recommendations can be found at: 

Dose Schedule

Zostavax should be administered immediately after it is reconstituted and is administered subcutaneously in the upper arm.

Effectiveness of the Vaccine

In a clinical trial of more than 38,000 individuals over 60 years of age, about half of whom received the vaccine, Zostavax reduced the occurrence of shingles by about 50%. Effectiveness was greatest in the younger age groups and declined with advancing age. In those who had received the vaccine and who developed shingles, the duration (but not the severity) of PHN was reduced.

Known Side Effects

Serious adverse events (death, hospitalization) were similar for vaccine and placebo recipients. Discomfort, redness or swelling at the injection site occurred in about 48% of vaccine recipients.

Related Issues

Duration of protection is not known at this time but appears to be more than 3 years.

Zostavax has not been studied in persons younger than 60 years.

Zostavax has not been studied among people who have already had shingles. Although recurrent cases of zoster have been described, someone who has had shingles is less likely to suffer another episode.

Key References and Sources of Additional Information

  • Hope-Simpson RE. (1965) The nature of herpes zoster: a long-term study and a new hypothesis. Proc R Soc Med 58:9-20
  • Oxman MN, Levin MJ, Johnson GR et al. (2005). A vaccine to prevent herpes zoster and postherpetic neuralgia in older adults. N Engl J Med 352:2271-84.
  • CDC. Provisional recommendations may be found at (Final recommendations are expected to be published in June, 2007).

Also see our image gallery of diseases.

Including available vaccines, history of the vaccine, who should and should not receive it, dose schedules, effectiveness, known side effects, and related issues.

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