Bedside rapid flu test and zanamivir prescription in healthy working adults: a cost-benefit analysis

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.

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.

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: RFT and conditional zanamivir prescription;systematic zanamivir prescription; and no zanamivir. A two-way sensitivity analysis was performed including the proportion of influenza-positive patients.

During influenza epidemics, systematic zanamivir prescription provided the best health outcome (0.81 influenza days averted) and minimised societal costs (reduced by 29.80 US dollars per person compared with no zanamivir; 1999 values). RFT with conditional zanamivir averted 0.65 influenza days and saved 14.40 US dollars 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 88.70 US dollars per patient consulting with influenza-like illness, and increased to 125.50 US dollars with systematic zanamivir and to 127.60 US dollars with RFT and conditional zanamivir.

Due to poor sensitivity of current RFT, systematic zanamivir prescription without RFT for unvaccinated healthy working adults should be recommended during influenza epidemics.