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A new vaccine called Zostavax is available to reduce the risk of shingles (herpes zoster) in people ages 60 and older.
"This vaccine gives health care providers an important tool to help prevent an illness that affects many older Americans and often results in significant chronic pain," says Jesse L. Goodman, M.D., director of the FDA's Center for Biologics Evaluation and Research.
Shingles is a disease caused by the varicella-zoster virus, the same virus that causes chickenpox. After an attack of chickenpox, the virus lies dormant in certain nerve tissue. As people age, it is possible for the virus to reappear in the form of shingles, which is estimated to affect 2 out of every 10 Americans during their lifetimes. Evidence of shingles includes clusters of blisters, which develop on one side of the body and can cause severe pain that may last for weeks, months, or even years after the virus reappears.
Zostavax, a live virus vaccine, has been shown to boost immunity against varicella-zoster virus. This is thought to be the mechanism by which the vaccine protects against zoster and its complications. The vaccine is given as a single injection under the skin, preferably in the upper arm.
Zostavax was studied in about 38,000 individuals 60 and older throughout the United States. Of these people, half received Zostavax, and half received a placebo. All study participants were then followed for an average of three years to see whether they developed shingles and, if they did, how long the pain lasted.
At the conclusion of the study, researchers found that, overall, the vaccine reduced the occurrence of shingles by about 50 percent in people ages 60 and older. It reduced occurrence by 64 percent in those ages 60 to 69.
The vaccine not only prevented approximately half of the cases, but also slightly reduced the duration of pain after the onset of shingles in people who developed the disease despite being vaccinated with Zostavax.
The most common side effects in people who received Zostavax were redness, pain and tenderness, swelling at the site of injection, itching, and headache. The percentage of significant adverse events observed in the study did not differ among those who received the vaccine and those who received the placebo.
As part of the vaccine development program, a smaller study was conducted to closely examine the vaccine's safety. In this smaller study, serious adverse events for all age groups were noted more frequently in those who received Zostavax than those who received placebo. Although the FDA has concluded that the available data do not establish that these events are related to the vaccine, the manufacturer will perform a Phase 4 (postmarket) study to provide additional safety information.
Zostavax is manufactured by Merck & Co. Inc., of Whitehouse Station, N.J.