Despite the decrease in total attack rate, the amount of drug usage increases with better sensitivity, mainly due to more people being correctly diagnosed and administered with antiviral drugs. This increase is not observed for the amount of testkits being used (figures 11 and 12). One interesting observation is that as the sensitivity of the testkits improves, the amount of drug usage becomes almost as much as if we were to assume that all patients are positively infected with pandemic influenza (figure 11). In some cases, the amount of drug dosage even exceeds the base approach D1 (e.g. figure 11 , policy P4c, diagnosis D2), possibly due to the higher total attack rate. Regardless of the testkit sensitivity, variations to the amounts of drug and testkit usage between diagnostic approaches D2 to D4 are not as significant as compared with the variations due to the different intervention policies being implemented.