Herpes zoster virus (i.e., shingles) vaccine (Zostavax) contains live, attenuated varicella-zoster virus in an amount that is approximately 14 times greater than that found in the varicella virus (i.e., chickenpox) vaccine (Varivax).¹ Herpes zoster vaccine has been approved by the U.S. Food and Drug Administration (FDA) for the prevention of shingles in persons 60 years or older. In addition, the Advisory Committee on Immunization Practices (ACIP) voted to recommend its use for the prevention of postherpetic neuralgia in this same age group.² The ACIP recommendations will become official when they are published in Morbidity Mortality Weekly Report, which is anticipated for this summer.

SAFETY

The overall safety of herpes zoster vaccine has been demonstrated in studies involving 21,000 patients.¹ based on a major clinical trial of herpes zoster vaccine, there appears to be no increased risk of varicella-like or zoster-like rashes after vaccine administration.³ A smaller study reported two cases of varicella-like rashes that contained the virus strain included in the vaccine, so the potential for such reactions cannot be ruled out.¹

Herpes zoster vaccine should not be used in patients who are immunosuppressed, including those with human immunodeficiency virus or those taking immunosuppressive doses of corticosteroids. no instances involving transmission of herpes zoster virus to close contacts of vaccine recipients occurred in clinical trials. However, based on experience with the varicella virus vaccine, such episodes may be possible.

Patients with an acute febrile illness (fever higher than 101.3°F [38.5°C]) should have vaccine administration postponed. Herpes zoster vaccine is FDA pregnancy category C, but it has not been studied in pregnant animals or humans, and pregnancy is listed as a contraindication on the product labeling.¹

TOLERABILITY

Approximately one third of patients receiving the vaccine will experience erythema, pain, or tenderness at the injection site. Systemic reactions have not been reported.

EFFECTIVENESS

Vaccine effectiveness is difficult to describe because not everyone who receives a vaccine is destined to develop the illness that the vaccine is designed to prevent. Herpes zoster vaccine decreases the occurrence of herpes zoster by approximately 50 percent, with 3.3 percent of unvaccinated persons developing herpes zoster compared with 1.6 percent of vaccinated persons. Vaccination prevents postherpetic neuralgia in approximately 66 percent of persons receiving the vaccine, although the absolute number of cases occur-ring in studies is small (approximately 0.4 percent of unvaccinated persons versus 0.14 percent of vaccinated persons). All of these results were shown in a randomized, blinded, placebo-controlled study of 38,546 persons 60 years or older who had no history of herpes zoster.³ Herpes zoster vaccine has not been studied in persons younger than 60 years. Over-all, about 60 patients will need to receive the vaccine to prevent one additional case of herpes zoster over the next three years. Roughly 360 patients will need to be treated to prevent one additional case of postherpetic neuralgia. The duration of the protective effects of herpes zoster vaccine has not been determined; current studies show that protection lasts at least four years.³

PRICE

The price of herpes zoster vaccine is approximately $186. Whether insurers or health plans will cover the vaccine will be determined on a plan-by-plan basis. Patients covered by Medicare may submit the cost of vaccination for reimbursement via Medicare Part D.

SIMPLICITY

Herpes zoster vaccine requires only a single subcutaneous dose to complete vaccination. Although it has not been studied in persons with a history of herpes zoster, the ACIP has voted to recommend its use in such patients,² thus making screening for eligible patients simpler. The herpes zoster vaccine should be kept frozen, and physicians should be careful not to confuse it with other similarly named vaccines (e.g., Varivax) or other frozen vaccines.

Bottom Line

Herpes zoster vaccine decreases the incidences of shingles and postherpetic neuralgia. Despite unresolved questions about cost-effectiveness,^4,5 and pending issues regarding reimbursement, it is an effective vaccine that should be offered to patients who are 60 years or older.