What causes herpes zoster (shingles)?
The causes aren’t completely known, but it is thought that a combination of factors can trigger shingles, including age 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)? The studies for Zostavax enrolled approximately 38,000 people throughout the United States who were 60 years of age and older; 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
