WASHINGTON — In an unusually close vote, an advisory panel to the Centers for Disease Control and Prevention on Wednesday recommended the use of a new vaccine to prevent shingles over an older one that was considered less effective.

The decision was made just days after the Food and Drug Administration announced approval of the new vaccine, called Shingrix and manufactured by GlaxoSmithKline, for adults ages 50 and older. The panel’s recommendation gives preference to the new vaccine over Merck’s Zostavax, which has been the only shingles vaccine on the market for over a decade and was recommended for people ages 60 and older.

The Advisory Committee on Immunization Practices also recommended that adults who have received the older vaccine get the new one. Even with the committee vote, this recommendation still awaits formal endorsement by the head of the C.D.C., which usually takes a couple of months. Insurance companies must also agree to cover the cost of the vaccine, which GSK estimates to be $280 for two doses.

According to the C.D.C., almost one of every three people in the United States will contract shingles, a viral infection that can result in a painful rash and lasting nerve damage.