Figure 7.

(a) Frequencies of replacement of strain 1 by strain 2 and (b) frequencies of eradication of both strains, estimated from 36 series of 1000 stochastic simulations for a range of vaccine cross-protection parameters (τ and η) from 0 to 0.95. Other parameter values are as in figure 5, except natural cross-protection θ=0.6 and ν=0.7. Only three outcomes were obtained in these series: initial extinction of strain 2 (not shown); (a) extinction of strain 1 only; (b) or extinction of both strains.