VariZIG™ can be obtained from the sole authorized US distributor, FFF Enterprise (Temecula, CA).  FFF Enterprises, at 1-800-843-7477 or via the Internet at www.fffenterprises.com.  FFF Enterprises delivers VZIG on an as needed basis (e.g., when there is an identified exposed person for whom VZIG is indicated). Under normal circumstances, the distributor delivers the vaccine within 24 hours of request.

The recommended dose is 125 U/10kg (22 lbs) of body weight, up to a maximum of 625 U. VariZIG™ should be administered intramuscularly as directed by the manufacturer. Currently, VZIG is available only in 625-U vials.

VariZIG™ treatment is expected to be most effective when it is initiated within 96 hours after exposure. Treatment after 96 hours is of uncertain value.  "In situations in which administration of VariZIG does not appear possible within 96 hours of exposure, administration of immune globulin intravenous (IGIV) should be considered as an alternative. IGIV should also be administered within 96 hours of exposure. Although licensed IGIV preparations are known to contain anti-varicella antibody titers, the titer of any specific lot of IGIV that might be available is uncertain because IGIV is not routinely tested for anti-varicella antibodies. The recommended IGIV dose for postexposure prophylaxis of varicella is 400 mg/kg, administered once. For pregnant women who cannot receive VariZIG within 96 hours of exposure, clinicians may choose either to administer IGIV or closely monitor the women for signs and symptoms of varicella and institute treatment with acyclovir if illness occurs. " [1]

When acyclovir therapy is indicated, the manufacturer recommends it should be initiated at the earliest sign or symptom of chickenpox. Acyclovir is given 800 mg intravenously 4 times daily for 5 days. There is no information about the efficacy of therapy initiated more than 24 hours after onset  of signs and symptoms. The dosage is adjusted for patients with renal impairment [2]

Acyclovir also been shown to be effective in preventing varicella in some susceptible persons when given prophylactically 800 mg PO five times daily for 5 to 7 days [3,4]. However, the CDC has advised "before such a strategy could be considered, additional data are needed concerning the prophylactic use of acyclovir in healthy and immunocompromised persons in all age groups." [5]