The Food and Drug Administration on March 24 expanded the approval of the shingles vaccine Zostavax for use in individuals aged 50-59 years.
The vaccine, manufactured by Merck & Co., was initially approved in 2006 for individuals aged 60 and older.
Approval of use of the live, attenuated virus vaccine in the younger age group was based on a multicenter, placebo-controlled study that involved more than 22,000 adults who had a history of varicella but were herpes zoster–negative. They were followed for a year after a single Zostavax dose. There were 30 confirmed cases of herpes zoster among the 11,211 Zostavax recipients, compared with 99 among the 11,228 who got placebo, for an efficacy rate of about 70%.
The most common side effects were redness, pain and swelling at injection site, and headache.
The FDA said that about 200,000 healthy Americans aged 50-59 years experience shingles each year and that the incidence increases with age.
"The availability of Zostavax to a younger age group provides an additional opportunity to prevent this often painful and debilitating disease," Dr. Karen Midthun, director of FDA’s Center for Biologics Evaluation and Research said in a statement.
The vaccine is contraindicated in people with a history of anaphylactic/anaphylactoid reaction to gelatin, neomycin, or any other component of the vaccine and in the immunocompromised.