What is herpes zoster (shingles) and how commonly does it occur?
Anyone who has had chicken pox is at risk for developing shingles. It is estimated that 1 million or more cases occur each year in the United States. Shingles can occur in people of all ages and 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. This is a sign that the virus, that has been dormant in the nerve cells, has reactivated and traveled from the nerves and followed a path out to the skin.
Because the nerves along the path become inflamed, shingles can also be painful. Pain that lasts for months after the rash has healed is called post herpetic neuralgia or PHN. For some people, this pain can be severe and chronic.
Does Zostavax help with post herpetic neuralgia?
In people who were 70 years of age and older, and still developed shingles, even though they had been vaccinated, Zostavax reduced the frequency of PHN, the pain associated with the illness. Overall, the benefit of Zostavax in preventing PHN is due to the effect of the vaccine on reducing the risk of developing herpes zoster (shingles). Zostavax will not work to treat PHN.
What causes herpes zoster (shingles)?
The causes aren't completely known, but it is thought that a combination of factors can trigger shingles, including aging and problems with the immune system.
How is Zostavax given?
Zostavax is given as a single dose by an injection under the skin, preferably in the upper arm.
How well does Zostavax work to prevent herpes zoster (shingles)?
For people 60 years of age and older, the studies for Zostavax enrolled approximately 38,000 people throughout the United States; approximately half received Zostavax and half received placebo. Study participants were followed on average for about three years to see if they developed shingles and if they did, how long the pain lasted.
At the conclusion of the studies, researchers found that overall (in persons age 60 years and older) the vaccine reduced the occurrence of herpes zoster (shingles) by about 50%. The vaccine effect was highest at 64% in people between the ages 60-69, but its effectiveness declined with increasing age; to 41% for the 70-79 age group, and 18% for those 80 years of age and older.
In those who were vaccinated with Zostavax, but still developed shingles, the duration of pain was a bit shorter for them versus those who received a placebo. Specifically, the pain of those in the Zostavax group lasted on average for 20 days and for those who received placebo, it lasted for about 22 days. The severity of the pain did not appear to differ among the two groups.
For people 50-59 years of age, approximately 22,000 people were studied; half received Zostavax and half received a placebo. Study participants were then monitored for at least one year to see if they developed shingles. Compared with placebo, Zostavax reduced the risk of developing shingles by approximately 70 percent.
Are there any possible adverse reactions associated with the use of Zostavax?
As with all medications, adverse reactions, including serious reactions, can occur. The most frequent adverse reactions reported for Zostavax were headache and injection-site reactions.
Who should not be immunized with Zostavax?
People who are allergic to neomycin, or any component of the vaccine should not receive Zostavax. Zostavax is a live vaccine and should not be given to individuals who have a weakened immune system caused by treatments that they are taking such as radiation, a class of drugs called corticosteroids, or due to conditions such as AIDS, cancer of the lymph, bone or blood.
In addition, Zostavax should not be used by women who are or may be pregnant.
Zostavax should not be used in children and it is not a substitute for Varivax, the vaccine to prevent chicken pox.
Also, people who are in close contact with pregnant women who have not had chickenpox should talk to their healthcare provider to decide if using Zostavax is right for them.
Should Zostavax be used in people who are under 50 years of age?
No, at this time, there is not enough information from the studies to determine the risks and benefits of Zostavax in people younger than 50 years of age.
Should someone who has already had shingles use the vaccine, so that they don't get them again?
An episode of shingles boosts immunity to the virus and may help protect you from getting shingles again. Although it is uncommon, some people may get shingles more than once. The effectiveness of Zostavax in preventing repeated episodes of shingles has not been demonstrated in clinical studies
How can I report a serious side effect with Zostavax, or other vaccines, to FDA?
Adverse reactions and other problems related to vaccines should be reported to the Vaccine Adverse Event Reporting System, which is maintained by FDA and the Centers for Disease Control and Prevention. For a copy of the vaccine reporting form, call 1-800-822-7967 or report on line to http://www.vaers.hhs.gov.