Cost effectiveness of early treatment with oral aciclovir in adult chickenpox.

Treatment of adult chickenpox with aciclovir is controversial because of the relatively high cost of medication and small proven benefits of therapy. A decision-tree model was used to estimate the cost effectiveness of aciclovir, from third-party payer and societal perspectives: the incremental cost per quality-adjusted life-year (QALY) gained was calculated for aciclovir treatment of chickenpox compared with no antiviral therapy in immunocompetent adults who presented within 24 hours of the onset of chickenpox rash. Incremental costs for aciclovir compared with no antiviral treatment were 42,900 US dollars per QALY gained, when viewed from a third-party payer perspective; however, results are sensitive to variation of clinical parameters. From a societal perspective, aciclovir therapy was cost saving compared with no antiviral treatment; aciclovir remained cost saving or cost effective (less than 50,000 US dollars per QALY gained) when probabilities, quality-of-life utility values and costs were varied within clinically plausible ranges, and when other scenarios for chickenpox severity and aciclovir effectiveness were examined. From a societal perspective, oral aciclovir is cost effective, and perhaps cost saving, when given within 24 hours of rash onset in adult chickenpox. The argument for antiviral use may be less strong when viewed from the perspective of a third-party payer.