FIG 5 .

Disease dynamics of a susceptible-infected-recovered pathogen with disease-caused mortality, where R₀ equals 2, without heterogeneity in susceptibility (A), with beta-distributed heterogeneity in susceptibility from experimental estimates (B), and with discrete all-or-nothing heterogeneity in susceptibility (C) (pale green dashed line, no vaccine protection; dark green dashed line, complete vaccine protection). The model is formally represented as the rates of change in a population of vaccinated (V), infected (I), and recovered (R) individuals. Susceptibility and vaccine protection parameters were determined by estimates of the beta distribution from the two-strain challenge experiment. Transmission, recovery, and disease-caused mortality parameters were not estimated from data. See Fig. S2 for the full range of R₀ values explored in model simulations.