Abstract
A live attenuated vaccine to prevent herpes zoster, or shingles (Zostavax; Merck & Co Inc, Whitehouse Station, NJ), is approved by the US Food and Drug Administration (FDA) for use in adults aged 50 years or older. Studies show that this vaccine is safe when administered to immunocompetent adults. Investigations are being conducted to evaluate the long-term safety and efficacy of the vaccine in immunocompromised populations, including patients who are dependent on steroids. The Advisory Committee on Immunization Practices (ACIP) of the Centers for Disease Control and Prevention recommends that this vaccine be routinely administered only to patients aged 60 years or older. As more data regarding duration of immunity after vaccination become available and as concerns regarding supply of this vaccine are adequately addressed, the ACIP plans to reconsider its recommendations regarding its use in patients aged 50 to 59 years. The author provides an overview of the herpes zoster vaccine, focusing on the latest extension in use approved by the FDA and the recommendations of the ACIP.
Herpes zoster (ie, shingles) will develop in approximately 1 in 3 persons during their lifetimes, resulting in an estimated 1 million episodes of herpes zoster in the United States annually.
1 Complications from herpes zoster, including chronic pain, scarring, loss of vision, and hospitalization (and any combination of these), occur in as much as 25% of cases.
1 One's risk for herpes zoster increases with age, as do the risks of complications that occur during and after the syndrome.
1 As summarized in the article by Hendriksz et al
2 in the present supplement to
JAOA—The Journal of the American Osteopathic Association, the primary varicella-zoster virus infection (ie, chickenpox) typically occurs in childhood or young adulthood. After the virus lies dormant for several years, it becomes reactivated in a dorsal root ganglion, leading to the symptoms of herpes zoster (eg, fever, headache, malaise, itching, severe pain down the nerve root, vesicular skin rash along the same dermatome) and subsequent sequelae and complications—primarily a neuropathic pain syndrome called postherpetic neuralgia (PHN).
3-5
In May 2006, the US Food and Drug Administration (FDA) licensed Zostavax (Merck & Co Inc, Whitehouse Station, NJ), a live attenuated vaccine for prevention of herpes zoster and its sequelae in adults aged 60 years or older.
6 This vaccine is not presently indicated for individuals who have received the varicella vaccine (Varivax; Merck & Co Inc) or children. In October 2006, the Advisory Committee on Immunization Practices (ACIP) of the Centers for Disease Control and Prevention recommended that Zostavax be routinely offered to adults aged 60 years or older—excluding immunocompromised persons or persons with known hypersensitivities—regardless of whether a history of shingles is evident (
Figure).
7
If our patients understood their risk of herpes zoster, the impact it could have on their lives, and the fact that herpes zoster could be prevented with a safe vaccine, I believe that many patients would be lining up at our doors to receive it—even if it meant getting a booster in 25 years. We are failing our patients by not advocating more on their behalf, by not educating them about the incidence and severity of shingles in older age groups, and by not strongly recommending vaccination that could prevent severe morbidity in their lives. The economic and psychological burden of herpes zoster in the aging population is substantial—with direct costs related to healthcare and indirect costs related to lost income and function and persistent, chronic, debilitating pain.
Important clinical questions that remain unanswered include the duration of immunity, whether Zostavax can be safely administered to patients who are immunosuppressed by illness (eg, human immunodeficiency virus) or by medications (eg, corticosteroids, chemotherapy), and whether the herpes zoster vaccine can be safely administered with the influenza vaccine. Limited data exist on administration of the herpes zoster vaccine with other inactivated vaccines, but the simultaneous administration of multiple inactivated vaccines is generally accepted and has not been shown to result in impaired immune response.
7,13
Postlicensure studies among the established cohorts from the initial trials that led to FDA approval of the herpes zoster vaccine will clarify information about duration of vaccine protection. Additional studies aimed at evaluation of the vaccine among immunocompromised patients—including individuals with human immunodeficiency virus infection, recipients of transplanted organs, and chronic users of steroids—are anticipated. If supply of the herpes zoster vaccine increases in a sustainable manner, the ACIP may revise its recommendations for the vaccine to include patients aged 50 to 59 years.
Financial Disclosures: Dr Weaver reports that she is a speaker for the vaccine division of Merck & Co, Inc.