Zostavax- Shingles preventive

September 14, 2006

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Company:

Merck

Pharmacologic class:

Vaccine

Active ingredient:

Varicella-zoster vaccine, live, attenuated; minimum of 19,400 plaque-forming units/0.65 mL dose; powder for subcutaneous (SC) injection after reconstitution with supplied diluent; contains neomycin, bovine serum albumin (trace); preservative-free.

Indication:

Prevention of herpes zoster (shingles) in adults >60 years of age.

Pharmacology:

Herpes zoster (shingles) results from the reactivation of dormant varicella-zoster virus (VZV), the virus that causes chickenpox as a primary infection. It is characterized by a unilateral, painful, vesicular cutaneous eruption. Although this rash is the most distinctive feature of shingles, the most frequent debilitating symptom is pain, which may occur before rash appears, during the eruption of the rash, or during the postherpetic phase. Zostavax boosts immunity against VZV, and it has been shown to be effective in preventing shingles in adults, but it is not indicated for treating an outbreak or for treating postherpetic neuralgia.

This vaccine is not a substitute for Varivax, and it should not be used in children.

Clinical trials:

In the Shingles Prevention Study, over 38,000 subjects >60 years of age received either a single dose of Zostavax or placebo and were followed for the development of zoster for up to 4.9 years. The study excluded persons who were immunocompromised or using corticosteroids on a regular basis, those with a history of zoster, and those with conditions that could interfere with the study evaluation (e.g., cognitive impairment or those who were nonambulatory). Zostavax was shown to significantly reduce the risk of developing shingles, compared with placebo. Vaccine efficacy was highest for those subjects who were 60-69 years of age and declined with increasing age. The overall efficacy for the vaccine was 51% for all age groups studied. For subjects in their 60s, the efficacy rate was 64%, and for those in their 70s, the rate was 41%. The efficacy rate for patients >80 years of age was 18%.

The study included all subjects who were followed for at least 30 days and did not develop an evaluable case of zoster within the first 30 days postvaccination.

Adults:

<60 years: not recommended. >60 years: one 0.65 mL dose by SC injection once in upper arm. Administer immediately upon reconstitution.

Children:

Not recommended.Contraindications: Immunodeficiency (e.g., HIV, leukemia, lymphoma, bone marrow or lymphatic cancer, immunosuppressive therapy). Untreated TB. Pregnancy (Cat. C; avoid pregnancy for at least three months after vaccination).

Precautions:

May defer in acute illness. Have epinephrine injection (1:1,000) available. May not protect 100% of recipients. Virus transmission may occur between recipients who develop rash and susceptible contacts. Nursing mothers.

Interactions:

High-dose corticosteroids: see Contraindications. Immunosuppressants (e.g., low-dose oral or daily topical or inhaled corticosteroids) may cause extensive rash or disseminated disease.