Shingles, which results from the reactivation of a dormant chickenpox virus later in life, usually brings with it a heaping of misery in the form of an itchy, painful skin rash, usually on one side of the body. Nearly 1 in 3 Americans will develop shingles, and an estimated 1 million cases surface in the United States each year, according to the Centers for Disease Control and Prevention. Shingles is not contagious but can spread chickenpox to people who haven't been exposed to the virus.
Shingles typically affects people 50 or older, people with medical conditions that hinder their immune systems or people receiving immune-suppressing drugs for conditions such as cancer. A federal advisory committee has recommended that people 60 and older get a vaccine in order to reduce the risk of shingles and its complications.
GSK's large-scale trial of its vaccine involved more than 15,000 patients age 50 and older in more than a dozen countries. The vaccine, which was given in two doses, reduced the risk of shingles by 97.2 percent compared to a placebo, the company said. The most common side effects were redness and swelling at the injection site, as well as muscle pain and headache, according to the study.
GSK has said it sees "significant potential" for its vaccine, which if approved could cut into the hefty revenue generated by Zostavax, produced by Merck. For now, the company said it plans to conduct additional trials to evaluate the ability of its vaccine to prevent shingles among people older than 70 and in adults with weakened immune systems.