Bedside Rapid Flu Test and Zanamivir Prescription in Healthy Working Adults: A Cost-Benefit Analysis

Background: Zanamivir, a neuraminidase inhibitor, reduces the number of days of illness in influenza-positive patients. New bedside rapid flu tests (RFT) should increase the number of influenza-positive patients whom receive zanamivir appropriately. Objective: To estimate the economic effects of implementing RFT and zanamivir among unvaccinated healthy working adults who consult within 2 days of the onset of influenza-like symptoms. Methods: We constructed a decision tree to perform a cost-benefit analysis from a societal perspective. Clinical outcome, i.e. number of influenza days averted, and societal costs were compared for three strategies: 1. RFT and conditional zanamivir prescription; 2. systematic zanamivir prescription; and 3. no zanamivir. A two-way sensitivity analysis was performed including the proportion of influenza-positive patients. Results: During influenza epidemics, systematic zanamivir prescription provided the best health outcome (0.81 influenza days averted) and minimised societal costs (reduced by $US29.80 per person compared with no zanamivir; 1999 values). RFT with conditional zanamivir averted 0.65 influenza days and saved $US14.40 per person. When the proportion of influenza-positive patients was under 39%, the no zanamivir strategy yielded the greatest societal savings; otherwise, systematic zanamivir was the dominant strategy. Medical costs associated with no zanamivir were $US88.70 per patient consulting with influenza-like illness, and increased to $US125.50 with systematic zanamivir and to $US127.60 with RFT and conditional zanamivir. Conclusions: Due to poor sensitivity of current RFT, systematic zanamivir prescription without RFT for unvaccinated healthy working adults should be recommended during influenza epidemics.