Figure 2.

Schematic of the whooping cough transmission model. Individuals progress from compartments S to I and I to R at rates of λ and γ, respectively. Individuals recently infected with measles progress from compartments S_M to I_M and I_M to R at rates of θλ and γ, respectively. Disease-induced mortality owing to whooping cough and measles are represented by α₁ and α₂, respectively. Here, M(t) is number of measles cases at week t. Immune mediation parameters are coloured red; θ quantifies the susceptibility to whooping cough after measles infection, α^M represents the risk of disease-induced mortality owing to whooping cough after measles infection, and n is the immune modulation duration. The slice size does not represent the actual size of S_M.