Figure 4.

The necessary frequency of treatments that will ensure the eventual elimination of active trachoma if only individuals under a certain age are treated. Although annual treatment may well eliminate disease if everyone in the population is treated, biannual treatment may be necessary if treatment is limited to children 1–10 years old. Results of the uncertainty analysis: black curve, 50th percentile; gray curves, 25th and 75th percentiles (based on data from Malawi). Adapted from Lietman et al [27].