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A new vaccine has been approved for use in the United States to reduce the risk of herpes zoster (shingles) in older adults. The vaccine was approved for licensing on May 26 by the US Food and Drug Administration (FDA) and is indicated for patients aged 60 years or older without compromised immune systems. It is expected to reduce by about 50% the risk of shingles, which is caused by a reactivation of the virus (varicella zoster) responsible for chickenpox. The new vaccine, zoster vaccine live (Oka/Merck) [Zostavax] is a higher dose version of one currently used to prevent chickenpox in children, Varivax. More than 90% of the US population has had chickenpox, and in most cases, the virus remains dormant for years in certain nerve cells. In some individuals, however, the virus reemerges when natural immunity wanes, causing pain and a blistering rash. A new vaccine that reduces the risk of shingles and severity of such symptoms as blistering rash and intense pain is available for older adults. (Photo credit: http://www.sciencesource.com) Between 40% and 50% of the estimated million cases of shingles reported annually in the United States occur in people aged 60 years or older. Up to 20% of these older adults will have an episode at some point in their lives. The vaccine targets the older population for two reasons, said Walter A. Orenstein, MD, associate director of the Emory Vaccine Center in Atlanta. “The more severe complications occur in this age group—specifically, the incidence of postherpetic neuralgia increases substantially with increasing age,” Orenstein said. “In addition, the incidence rates of disease are greater in the elderly age group; thus you get more efficiency in cases prevented per dose administered.” Zoster vaccine joins vaccines for influenza and pneumococcal pneumonia as weapons to reduce disease risk in adult populations, said Jesse Goodman, MD, director of the FDA's Center for Biologics Evaluation and Research. “We're primarily used to vaccination of children, and in children, vaccines have been among our most effective interventions to protect individual and public health,” he noted at a press conference announcing the approval of the zoster vaccine. “The vaccine we're discussing today is part of the concept of the increasing use of vaccine to benefit adults.” Goodman said the vaccine does not prevent infection by the varicella-zoster virus and that it should be considered a booster vaccine that increases a person's immunity to help prevent the virus from re-emerging as shingles. The vaccine will be given as a single dose by injection under the skin. Each 0.65-mL dose contains a minimum of 19 400 plaque-forming units (about 14 times the amount found in the childhood chickenpox vaccine) of the Oka/Merck strain of live, attenuated varicella-zoster virus. Orenstein said the zoster vaccine moves the science closer toward developing therapeutic vaccines to prevent or ease symptoms after a pathogen has infected the body. Vaccines are generally given to individuals who have no prior exposure to an organism to try to prevent infection from occurring or to keep infection in check, he said. “Here we’ve found that with a 14-fold increase in the potency of the [chickenpox] vaccine, you can keep the virus in check and reduce the incidence of zoster.” For Orenstein, the zoster vaccine's success gives hope of developing analogous vaccines to prevent disease resulting from other chronic infections, such as herpes simplex and cytomegalovirus. Some scientists also believe that a similar strategy could one day be used against HIV and tuberculosis, although Orenstein warned such theories are preliminary. Positive study Positive study The FDA’s licensing of the zoster vaccine to its manufacturer, Merck & Co Inc, Whitehouse Station, NJ, followed last year's published findings of the Shingles Prevention Study Group (Oxman MN et al. N Engl J Med. 2005;353:2271-2284). In that randomized, double-blind, placebo-controlled trial of 38 546 adults aged 60 years or older who were followed for a median of 3.1 years, the researchers found that the vaccine not only reduced the incidence of shingles by 51.3%, but that it also reduced illness severity by 61.1% and decreased the incidence of postherpetic neuralgia by 66.5%. Positive study For Michael Oxman, MD, chairman of the Shingles Prevention Study Group, several intriguing questions remain, such as how long the boost in immunity lasts and if even higher doses of the vaccine would provide greater protection. Some scientists also theorize that some people receive natural boosts to their immunity to varicella zoster virus over the course of their lifetime, such as parents' exposure to the virus when their children get chickenpox. However, Oxman noted, widespread use of the chickenpox vaccine since the middle of the 1990s means such natural boosts to immunity will be lost. As a result, it is possible that people will develop shingles in greater numbers, or perhaps earlier in life, such as in their 40s. Shingles symptoms tend to be less severe in younger patients, and it is possible that a bout of shingles in early middle age might provide additional immunity against an attack later in life, when symptoms are typically more severe. Positive study “There are lots of models to show us what may happen, but models are not enough; we must observe,” said Oxman, who is also a professor of medicine and pathology at the University of California, San Diego. “Hopefully, the CDC [Centers for Disease Control and Prevention] will be wise enough to fund such observational studies for 50 years so we can find out.” Positive study Merck also has some questions it would like to answer in subsequent studies of the vaccine. According to a company spokeswoman, the pharmaceutical manufacturer is conducting long-term safety studies in 32 000 people and will look at expanding vaccine use into people in their 50s. Real-world relevance Real-world relevance Oxman said he would recommend the vaccine for everyone older than 60 years who is not immunosuppressed; it is not advised for patients who have had shingles because shingles itself naturally boosts immunity. Real-world relevance With an estimated 44 million US individuals older than 60 years, the patient population eligible for the vaccine appears quite large. But the real question, Oxman noted, is who will pay for it? Merck has priced it at about $150 per dose, not including cost of physician services. In justifying its pricing, Merck noted its research suggested that annually in the United States shingles results in $750 million in direct medical costs and $1.25 billion in indirect costs. Real-world relevance The company said the vaccine is available now; if the CDC's Advisory Committee on Immunization Practices votes during its October meeting on recommendations for whom the vaccine is appropriate, insurance coverage may follow. Medicare coverage has not yet been determined. Federal payment (Part B) for the administration and professional fees are permitted only for designated preventive and medically necessary vaccines, a status not yet established for the shingles vaccine. When asked whether Medicare would consider Part B payments for the zoster vaccine, a spokesperson with the Centers for Medicare & Medicaid Services said, “Not at this time.” Real-world relevance Such inaction by Medicare bothers Orenstein. Real-world relevance “The FDA has concluded [zoster vaccine] is a safe and effective vaccine,” Orenstein said. “To deprive the people of its benefits would be a mistake.” Shingles Resources Shingles Resources News, overviews, clinical trials, and other resources relating to shingles. Available at http://www.nlm.nih.gov/medlineplus/shingles.html Shingles Resources Details on the diagnosis and treatment of varicella disease, or chickenpox. Available at http://www.cdc.gov/nip/diseases/varicella/faqs-gen-disease.htm Shingles Resources Information about shingles and postherpetic neuralgia from Beth Israel Medical Center's Department of Pain Medicine and Palliative Care. Available at http://www.stoppain.org/pain_medicine/content/chronicpain/shingles.asp Shingles Resources Interactive tutorial on shingles. Available at http://www.nlm.nih.gov/medlineplus/tutorials/shingles/htm/index.htm
JAMA – American Medical Association
Published: Jul 12, 2006
Keywords: herpes zoster disease,vaccines,shingles vaccine
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