FIGURE 1. Data.

a, Modelled population density of Thailand and 100-km contiguous zone of neighbouring countries, based on Landscan²⁴ data and plotted on a logarithmic scale (light for low density, dark for high density). Inset shows Bangkok in more detail. b, Age distribution of Thai population in 2003 in 5-yr bands (blue), and the corresponding age distribution of the simulated population (red). c, As b but showing distribution of household sizes. d, Observed (solid lines) and modelled (dashed lines) distributions of school sizes (blue, elementary; green, secondary; red, mixed). e, Probability of travelling over a certain distance to work, estimated from data (blue) and from the simulated population (red). f, Weekly excess influenza-related mortality in 1918−1919 in Great Britain (red), and corresponding estimates of the reproduction number R (blue), calculated assuming T_g = 2.6. g, Viral shedding data for experimental influenza infection¹⁵ (expressed in tissue culture infective doses (TCID₅₀) per ml of nasal lavage fluid) compared with the modelled profile of infectiousness over time. Note that the infectiousness profile was not fitted to shedding data. See Methods and Supplementary Information for more details.