Differences in IC50 (nM) calculated on relative slope between time intervalsa versus total fluorescent unitsb for A/Mississippi/03/01 and A/Fukui/45/04 wild type viruses.

aIC50s for FU are based on the drug concentration resulting in 50% inhibition of the uninhibited control FU.bRates in FU/min are calculated for each drug concentration for each time interval and the IC50 is the drug concentration which inhibits the rate of the uninhibited control by 50%. This approach separates each reaction time so it is independent of the rates of preceding time intervals.