FIG 1 .

Best-fitting models (lines) for infection response of vaccinated and unvaccinated fish challenged with escalating concentrations of IHNV in PFU (plaque forming units) per microliter (points ± standard errors). Dashed lines show model fit where all unvaccinated individuals were equally susceptible (homogeneous) and vaccinated individuals had heterogeneous susceptibility distributed according to a beta distribution. Solid lines show model fit allowing for gamma-distributed heterogeneity in susceptibility in unvaccinated fish. Vaccinated fish have gamma-beta-distributed heterogeneity in susceptibility where parameters of the gamma distribution are determined by heterogeneity in susceptibility of the unvaccinated fish.