Viral fitness as a function of γ . Plot of viral fitness (measured by R0) as a function of the advantage parameter γ. For this figure, β
=1 , β
= 0.5, τ = 0.2, θ = 0.25, ν = 0.14, δ = 0.05, μ = 0, ε = 0. Slicing through the graph vertically at a fixed value of γ allows us define the fitness orderings in Table 3.