A federal expert panel Wednesday recommended a new and more effective shingles vaccine to protect adults 50 and older from a painful rash that affects 1 in 3 people during their lifetime.

In a rare move, the Advisory Committee on Immunization Practices also recommended, by an 8-to-7 vote, that the new Shingrix vaccine be preferred over the existing Zostavax vaccine because it provides far greater protection and is expected to prevent significant disease, especially among the elderly. The Food and Drug Administration approved the new vaccine, made by GlaxoSmithKline PLC, on Friday.

Shingrix is the first new vaccine for shingles in a decade, and it's the first time the panel is recommending that adults between 50 and 59 be vaccinated — a group that numbers about 42 million Americans. The panel also recommended that anyone who previously was vaccinated with the Zostavax vaccine be revaccinated with the new vaccine — an estimated 20 million people.

“This represents a major advance for people who want to be protected against the disease and its complications,” said Kathleen Dooling, a medical officer with the Centers for Disease Control and Prevention. The new vaccine has the potential to prevent tens of thousands of cases of shingles and thousands of cases of its most common complication, a debilitating nerve pain, she said.

The most common side effect is reaction at the injection site, including redness or swelling, muscle pain, fever and headache. The side effects can last up to three days.

Recommendations from the panel are usually adopted by the CDC, which sets the immunization schedule for children and adults. The recommendations will be sent to the CDC director and, if approved, will be published as policy early next year.

Here are some of the most common arguments for and against vaccination. (The Washington Post)

There was vigorous debate among panel members about recommending the new vaccine over the existing one. 

“This is certainly the closest vote in my experience at ACIP,” said Nancy Bennett, a professor of medicine and public health sciences at the University of Rochester who chairs the committee. Although she said the discussion was “fantastic,” she also noted that “it's hard to have a divided committee.”

Members agreed that data from clinical trials show the superior effectiveness of the new vaccine. But those who opposed a preferential recommendation raised concerns about the lack of data on its performance among minority groups and on the vaccine's safety and effectiveness in a real-world setting. The vaccine requires two doses, compared to the existing vaccine, which is given in one shot. 

“It's never been given outside a research setting,” said Cynthia Pellegrini, senior vice president for public policy at the March of Dimes.

Others said the greater effectiveness and its longer-lasting protection were the most important factors, noting that CDC and others will be continually monitoring the vaccine's safety.

“Based on the information I have seen today, how would you explain not advising someone get a vaccine that is expected to prevent serious disease more effectively than another product?” asked Jeff Duchin, a health officer for Seattle and King County.

 The panel has historically been reluctant to make these preferential recommendations on specific products, so doing so “is a big deal,” William Schaffner, a member of the panel's shingles vaccine working group, said in an interview. 

By recommending that adults start receiving the vaccine at age 50 — a decade earlier than the current recommendation — the advisory committee is hoping that millions more people will be afforded protection from shingles, which is caused by the chickenpox virus, and its complications. 

Shingrix is 97 percent effective against shingles for those 50 to 59 years old, compared to about 70 percent for Zostavax, data show. For those in their 60s, the new vaccine is 97 percent effective, compared to 64 percent for Zostavax. For those in their 70s, Shingrix is 91 percent effective, compared to about 41 percent for Zostavax.

And for those in their 80s, who are most at risk of developing complications, the new vaccine is about five times more effective: 91 percent versus 18 percent. 

Shingrix is also 91 percent effective in preventing the most common complication of shingles in those 50 and older. That nerve pain, known as post-herpetic neuralgia, is felt in areas where the shingles rash occurred and can last for months and even years. In some cases, the physical discomfort can be so debilitating that the touch of clothing on the skin can cause searing pain. It has no treatment or cure, and doctors say it has driven patients to contemplate suicide.

The new vaccine's protection remains high four years after vaccination, data show. There is very little data to know how effective the new vaccine is with just one dose, CDC's Dooling said.

The older vaccine, Zostavax, made by Merck, has been licensed since 2006. Its one dose is 67 percent effective against severe nerve pain in the first four years, according to data presented at the meeting. But Zostavax's protection drops after the first year, and it offers virtually no protection after nine years.

Anyone who has had chickenpox — which these days means nearly everyone over 40 — harbors the varicella-zoster virus that causes the disease. The virus can resurface decades later, resulting in painful blisters on one side of the body or face. The risk of developing shingles increases with age. 

The United States has an estimated 1 million cases of shingles each year, according to CDC. About half of all cases occur in people 60 and older. About 1 in 5 people who get shingles develop that debilitating nerve pain. Shingles can also lead to pneumonia, hearing problems, blindness and brain inflammation.

GlaxoSmithKline has said the price of Shingrix will be $280 for the required two shots. Merck’s one-shot Zostavax costs $223. Most insurance plans cover the shingles vaccine.

The two products are made differently. GlaxoSmithKline’s vaccine is genetically engineered and includes an ingredient that boosts effectiveness of the immune system. As people age, their immune response weakens. 

Merck’s vaccine uses a live but weakened virus, which means it can’t be given to people with compromised immune systems.

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