Merck (NYSE:MRK), known as MSD outside the United States and Canada, announced today that data from the pivotal Phase III study with ZOSTAVAX ® (Zoster Vaccine Live) in adults ages 50 to 59 were published in the April 1 issue of Clinical Infectious Diseases. In this study, ZOSTAVAX, Merck's vaccine for the prevention of herpes zoster, commonly known as shingles, significantly reduced the risk of developing shingles by nearly 70 percent in adults ages 50 to 59, compared with placebo. The results from this study provided the data that supported the U.S. Food and Drug Administration’s (FDA) expanded indication for ZOSTAVAX in March 2011 in this age group. ZOSTAVAX is the only shingles vaccine licensed for use in the United States. “The results of this study demonstrate the importance of ZOSTAVAX to help prevent shingles in adults ages 50 to 59. More than 95 percent of adults 50 and older have had chickenpox, putting them at risk for developing shingles," said Myron Levin, M.D., one of the study’s investigators, and professor of pediatrics and medicine, University of Colorado Denver School of Medicine, Section of Pediatric Infectious Diseases, The Children's Hospital. According to the U.S. Centers for Disease Control and Prevention (CDC), in the United States approximately 1 in 3 people will experience shingles in their lifetime, and nearly one million cases of shingles occur each year. The incidence and severity of shingles increase with age, with an estimated 70 percent of annual cases occurring in people 50 years of age or older. Once a person has had chickenpox, the varicella-zoster virus stays inside the body and can resurface later as shingles. The CDC currently recommends a single dose of ZOSTAVAX for all appropriate people 60 years of age and older, regardless of whether they have had a prior case of shingles, noting that persons with chronic medical conditions may be vaccinated unless their condition constitutes a contraindication.