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.