FDA Approves First Shingles Vaccine

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The agency cleared the vaccine -- known as Zostavax -- for use in adults age 60 and older: studies showed it can prevent shingles roughly half the time.

But experts say they're worried that partial insurance coverage of the vaccine may slow its acceptance by doctors and patients.

Shingles causes a rash with blisters that usually lasts for two to four weeks. The pain associated with the blisters can be quite intense. Once this initial phase is over, nerve pain called postherpetic neuralgia can set in. This pain lasts anywhere from 30 days to months or even years. It can be so severe in some people that it disrupts their lives.

The illness is caused by varicella, the same virus that causes chickenpox. Shingles occurs when the chickenpox virus lying dormant in nerve cells "wakes up" in older people or others with health problems. The vaccine, Zostavax, is actually a boosted dose of the chickenpox vaccine currently given to children.

Postherpetic neuralgia is more common in people older than 60. It occurs in less than 10% of people younger than 60 after a bout of shingles but in more than 40% of people older than 60.

Large Market for Vaccine

There are approximately 50 million Americans over age 60: more than 95% had chickenpox as children, making them vulnerable to shingles.

"The market is large," says Christine Fanelle, a spokeswoman for Merck & Co., the vaccine's manufacturer.

The company originally sought approval to sell the vaccine to adults 50 and older. But the FDA declined after expert advisors said in December 2005 that Zostavax hadn't been studied in patients younger than 60. The agency also rejected a bid to approve the vaccine for preventing postherpetic neuralgia.

Up to one in ten older patients won't be candidates for the vaccine because of weakened immune systems due to cancer therapy, organ transplants, HIV/AIDS, or other causes. The vaccine contains live but weakened varicella virus that could overwhelm the immune systems of those patients.

David Markovitz, MD, a professor of internal medicine at the University of Michigan who reviewed Zostavax for the FDA, calls it a "highly useful" vaccine. "It's clear the vaccine markedly reduces the incidence" of shingles, he says.

Markovitz says that doctors may be tempted to offer "off-label" vaccinations to adults age 50 to 59 in hopes of providing earlier protection against shingles. "Off-label" refers to drugs that are used in ways that have not been not approved by the FDA. But he stressed that the vaccine remains unstudied in such patients and that researchers still don't know how long immunity lasts after vaccination.

"I don't think I would rush out and get it myself," Markovitz, who is 52, tells WebMD.

Insurance Coverage Worries

Other experts worried about the vaccine's cost. Zostavax is slated for coverage under Medicare's Part D prescription program. But under the program, individual private insurance plans set prices, meaning that coverage for the vaccine could vary substantially among hundreds of plans nationwide.

Medicare and private insurers often base coverage decisions on counsel from the Advisory Committee on Immunization Practices (ACIP) at the CDC.

The committee is expected to make recommendations next fall advising the government, insurers, and doctors, on how many older Americans should receive the shingles vaccine.

Insurance coverage inside and outside of Medicare could have a large impact on how many adults seek the vaccine. "We certainly think that's very important," Fanelle says.

William Schaffner, MD, chair of the department of preventative medicine at Vanderbilt University and an ACIP member, says that partial insurance coverage could impede lower-income people from purchasing the vaccine and limit its spread among patients who could benefit.

"Many of us are distressed about that possibility," notes Schaffner, who says he received financial payment from Merck to discuss Zostavax with reporters.

Follow-Up Study

The company followed patients in its study for four years. Officials told the FDA that they plan to follow patients for 10 years to determine how long patients retain immunity before requiring boosters. The company is also planning to study the vaccine in immunocompromised patients, officials said in December.

Markovitz says the company's original study focused on whites and that the company should also expand testing in minorities, who can have varying immune responses.

"Realistically, we can say this works in white people, and it's just too bad this continues to happen in every darn study," he said.