Figure 4. Effect of initial efficacy (a–c), vaccine half-life (d–f) and degree of heterogeneity (g–i) on the number of events averted per 1000 person years by PEV for the reference transmission setting of EIR 21.

Results obtained assuming vaccine efficacy of 52%, a vaccine half-life of 10 years and homogeneity value of 10, unless the values are varied along the x-axis. Vaccines are distributed via EPI (circles), EPI with boosters (*) and EPI with 70% mass vaccination (squares).