Fig. 3.

a The difference in population immunity due to differences in maternal immunity (i.e., the difference between Fig. 2c and d). b Difference in population immunity for maternal immunity waning at 3 months between regions with a developed and developing age structure (i.e., the difference between Fig. 2b and d). Note that the target ages of vaccination which minimize the difference due to a difference in maternal immunity are where the difference due to a difference in age structure starts to increase