Seroepidemiology of trachoma for the elimination endgame

The overall objective is to advance the methods used for the design and analysis of trachoma serology surveys. This involves assembling a large, contemporary global dataset for trachoma serology across a gradient of endemicity, paired with clinical signs and molecular measures of infection (>100,000 blood specimens tested in 19 studies from 2010-2024). Aim 1: Develop robust methods to translate antibody response into population-level measures of transmission from endemic settings to post-elimination. This includes estimating age-seroprevalence curves semi-parametrically, deriving summary measures (e.g., seroprevalence, force of infection), and comparing serologic measures between populations of different endemicity, and with other measures of trachoma (PCR infection, clinical signs) across geographic scales. Aim 2: Determine if model-based geostatistics improve the efficiency of serological survey design and enable finer scale targeting of control programs as populations approach elimination. This involves applying recent advances in geospatial design to trachoma serology in analyses of 11 georeferenced studies, comparing prevalence estimates with current standard methods, and studying the impact of using spatial predictions to target azithromycin at finer spatial scales.