In order to estimate health system resource needs and gaps for a pandemic influenza scenario, we used a mathematical model previously developed as part of the AsiaFluCap project to simulate the transmission dynamics of a pandemic influenza outbreak [22] . Full details and equations of the model can be found in [22] , and are summarized in Text S1. Briefly, the model is based on a deterministic SEIR (Susceptible-Exposed-Infectious-Recovered/removed) model described by differential equations tracking number of people in each compartment over time. Given that the primary aim of this analysis was to provide relative estimates of resource gaps within and across countries, rather than to accurately simulate the spread of pandemic influenza throughout each country, the model structure was kept relatively simple, with homogeneous mixing patterns and no age-structure assumed within the modeled population. However, novel complexity is incorporated through making parameters describing the clinical course of infected individuals conditional upon the availability of certain key health system resources (antivirals, beds, and ventilators). Thus we could obtain relative indications of the consequences of resource shortages on the pandemic disease burden, specifically in terms of ''avoidable deaths'', which we define as deaths that would not have occurred in the presence of sufficient resources.