WASHINGTON >> In an unusually close vote, an advisory panel to the Centers for Disease Control and Prevention today 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 more than 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 CDC, 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 CDC, 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.

The disease, also known as herpes zoster, can range in severity from barely noticeable to debilitating. It is caused by the varicella-zoster virus, which also causes chickenpox.

Once a person has had chickenpox, the virus lies inactive in nerve tissue. Years later, it may reactivate as shingles. The CDC estimates that about 1 million cases are diagnosed in the United States each year.

Given in one dose, Zostavax had shown a 51 percent reduction in shingles and a 67 percent reduction in nerve pain. Shingrix is given in two doses, and the company said clinical trials showed it to be about 98 percent effective for one year and about 85 percent over three years.

By preventing shingles, the vaccine also drastically reduces the overall incidence of severe nerve pain, a lasting complication for about 1 in 3 people who get shingles. GlaxoSmithKline said it tested the vaccine in more than 38,000 people.

“We believe Shingrix will provide confidence in the protection one can expect from a shingles vaccine,” said Luc Debruyne, the company’s president of global vaccines.

The recommendation of the advisory committee will be considered an endorsement of Shingrix over Zostavax, although the closeness of the committee vote, 8-7, may mitigate the market loss for Merck.

Dr. Kathleen Dooling, a medical officer in the CDC’s division of viral disease, said she expected the agency’s final recommendation to be issued early next year.

“The Shingrix vaccine has the potential to prevent tens of thousands of cases of shingles and its complications,” Dooling said.

She cautioned, however, that more people had adverse reactions to Shingrix than to Zostavax, including fever and muscle aches.

“Patients and health care providers should be aware that this vaccine is very effective, but it also causes more reactions than they may be used to with other adult vaccines,” she said. “All indications are these are not dangerous to one’s health, but they may interfere with your daily activities for a few days.”

GlaxoSmithKline said its new vaccine would cost about $280 and would be available next month. Zostavax costs about $223.