Fig. 4.

Estimated total population seroprevalence and prevalence of prior infection in the unvaccinated population at each survey round, by region (top) and district of Ulaanbaatar (bottom). Unsampled districts of Ulaanbaatar are shown in grey on district level maps, and are merged with the surrounding Central region on country maps for simplicity. Confidence intervals are presented in Tables S5 and S7. Note that samples for Ulaanbaatar were generally collected later that in the regions and are not directly comparable (see Fig. 2 and Table S4).