An insufficient drug stockpile is a real world issue faced by all countries. For instance, the United States has only enough antiviral medicine for 25 per cent of its population (US Department of Health & Human Services 2005). In order to conserve limited drug supplies, different countries have implemented policies that prioritize intended drug recipients according to their risk groups (US Department of Health & Human Services 2005). In addition, prophylaxis is only administered if deemed necessary. However, Longini et al. (2004) demonstrated that targeted antiviral prophylaxis could be an effective measure for containing influenza until the proper vaccines are developed. Here, some of the intervention policies include prophylaxis being given to contacts. In addition, to prevent drug wastage, we tracked the actual amount of drugs being consumed by the contact. If the contact becomes symptomatic later on and is subsequently diagnosed with pandemic flu, he/she will only be issued enough drugs to top-up his/her current supply to the required dosage levels as per index cases. Taking into account that not all patients will be upfront about the amount of drugs they already have, we set the average declared amount to be 50 per cent of the actual dosages remaining.