ANTIVIRAL PROPHYLAXIS AND TREATMENT IN CHICKENPOX - A REVIEW PREPAREDFOR THE UK ADVISORY GROUP ON CHICKENPOX ON BEHALF OF THE BRITISH-SOCIETY-FOR-THE-STUDY-OF-INFECTION

Prophylactic intervention with varicella-zoster immunoglobulin early i n the incubation period can prevent or attenuate the disease manifesta tions of varicella in susceptible contacts at high risk from this infe ction. Detailed guidelines are issued in the UK Department of Health p ublication on Immunization against Infectious Disease. Sensitive immun oassays are available for investigation of antibody status and subclin ical seroconversion. Live attenuated varicella vaccine, which has been used successfully post-exposure as web as electively elsewhere, is at present not generally available in the UK. Effective protocols for pr ophylaxis against varicella with the antiviral agent aciclovir are not pet established. The nucleoside analogue aciclovir (syn: acyclovir, Z ovirax(TM)) is effective in inhibiting replication of VZV when given a t a dosage higher than that required for treatment of HSV, and is curr ently the only available and approved treatment for varicella in the U .K. Intravenous aciclovir therapy for 5-10 days is effective for varic ella in neonates and the immunocompromised, and for varicella pneumoni a or other complications in adults and children, if begun early. Oral aciclovir is only effective if begun with 24 h of onset of rash. With that proviso, it is recommended for treatment of varicella in otherwis e healthy adults and adolescents, but not for routine use in children under 13 years of age unless they are sibling contacts or have other m edical conditions. Aciclovir has a high therapeutic index and good saf ety profile, but caution is advised with use in pregnancy.