From the third-party payer perspective the incremental cost per QALY gained from aciclovir treatment was $42,900. From the societal perspective, aciclovir was found to be cost saving compared with no antiviral treatment and no cost-effectiveness ratio was presented.
From the third-party payer perspective the one-way sensitivity analyses showed the incremental cost-effectiveness of aciclovir to be sensitive to illness utility values, degree of symptomatic relief and shortening of illness provided by aciclovir. Variation of these parameters could increase the incremental cost-effectiveness ratio to over $50,000 per QALY gained. The model was also found to be sensitive to the assumption that aciclovir does not affect chickenpox-related hospitalisations or deaths. Under the assumption that aciclovir can reduce these outcomes, the incremental cost-effectiveness ratio decreased significantly. There was no reporting of any sensitivity analysis of costs.
From the societal perspective, the one-way sensitivity analyses found the model to be sensitive only to variations in aciclovir related shortening of illness, or to variation in medication costs. Changes in these variables made aciclovir cost-generating rather than cost-saving. If days of illness were shortened by less than 1.63 days but greater than 0.17 days (baseline value 1.8 days), the cost per QALYgained remained less than $50,000. Likewise, if medication costs were greater than $137.20 but less than $282, the cost per QALY gained from aciclovir remained less than $50,000.