Herpes varicella-zoster virus (VZV)
Therapy should be initiated at the earliest sign or symptom of herpes zoster and is most effective when started generally within 72h of the onset of zoster rash.
Zoster confined to dermatome (normal or immunocompromised patients):
Visceral, central nervous system, or disseminated VZV infections, and zoster in severely immunocompromised patients:
Acyclovir 10 mg/kg (500 mg/m 2 in children < 12y) IV q8h for 7-10d
Zoster vaccine live (Zostavax)
Used for the prevention of herpes zoster (shingles) in patients ≥ 50y; not used for the treatment of herpes zoster 
Administer 0.65 mL (entire vial contents) subcutaneously in the deltoid region of the upper arm
Note: In March 2011, the Food and Drug Administration (FDA) lowered the approved age for use of Zostavax to 50-59y. Zostavax was already approved for use in individuals aged 60y or older. Annually, in the United States, shingles affects approximately 200,000 healthy people aged 50-59y.
Approval was based on a multicenter study, the Zostavax Efficacy and Safety Trial (ZEST).  The trial was conducted in the United States and 4 other countries in 22,439 people aged 50-59y. Participants were randomized in a 1:1 ratio to receive either Zostavax or placebo. Participants were monitored for at least 1y to see if shingles developed. Compared with placebo, Zostavax significantly reduced the risk of developing zoster by approximately 70%.