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Purpose: To evaluate combinations of clinical signs, using a modified World Health Organization (WHO) grading scheme, to predict a very low prevalence of infection at the community level after at least three rounds of mass drug administration (MDA)., Methods: Seventy-one villages had three to seven rounds of MDA. A random sample of 7828 children ages 5 years and younger was evaluated for trachoma, and determination of Chlamydia trachomatis infection was made. Proportions of children positive for infection were evaluated against all possible combinations of follicular trachoma (TF) and inflammatory trachoma (TI). High-risk signs (HRS) for infection were defined as those indicating the infection prevalence was >20%. The sensitivity and specificity of prevalence of HRS in identifying communities with infection was examined., Results: The median community infection prevalence was 3.8% interquartile range (IQR) (1.8%, 7.7%); the median trachoma prevalence was 9.4%, IQR (6.6%, 15%). Severe TI, combination of TF and TI (WHO criteria), or severe TF with signs of inflammation were predictive of infection in the community, but the absence of these HRS was not an indicator of low infection rates., Conclusions: The use of HRS to determine the infection status of a community was not useful in predicting whether MDA could be stopped.

Purpose: Mass treatment with azithromycin for trachoma endemic communities typically excludes infants under age 6 months, whose parents are provided with tubes of tetracycline to administer daily over 4 to 6 weeks. The authors sought to determine whether infants aged <6 months are a source of re-emergent infection in their families after mass treatment in trachoma-endemic communities., Methods: In a longitudinal study of all children aged less than 10 years in four communities, the authors identified 91 infants aged <6 months living in 86 of 1241 households. All children aged

Objectives: Trachoma is the principal cause of infectious blindness. As part of its strategy to eliminate trachoma, the World Health Organization recommends annual mass antibiotic treatment for at least 3 years with an 80% population coverage target. However, to date, ideal population coverage and mass treatment duration have not been determined and further evaluation of treatment recommendations in areas of varying endemicity is warranted. The studies presented here evaluate the impact of coverage level and frequency of mass treatment with single dose azithromycin on trachoma and ocular C. trachomatis infection., Methods: The Partnership for the Rapid Elimination of Trachoma supervises 2 randomized, community-based clinical trials in Tanzania and The Gambia. Although each trial is a stand-alone effort, protocols, data collection, and analytic approaches have been harmonized to permit generalizations. Communities in each site were randomized using a 2X2 factorial design to standard (80%-90.0%) versus high (over 90.0%) treatment coverage; communities were further randomized to annual treatment for 3 years versus a "graduation" rule where evidence indicates an absence of follicular trachoma or infection and annual treatment is halted., Results: Average prevalence of follicular trachoma in children age less than 5 years was 32.2% in Tanzania and 5.96% in The Gambia. Randomization appeared to be effective, as prevalence was not statistically different between the arms within each country., Conclusions: There are challenges in harmonizing 2, large trials in Africa. Study outcomes will provide critical data to national trachoma control programs on treatment methodology and resource allocation toward elimination of the disease.

Background: Mass treatment to trachoma endemic communities is a critical part of the World Health Organization SAFE strategy. However, non-participation may not be at random, affecting coverage surveys and effectiveness if infection is differential., Methodology/principal Findings: As part of the Partnership for Rapid Elimination of Trachoma (PRET), 32 communities in Tanzania, and 48 in The Gambia had a detailed census taken followed by mass treatment with azithromycin. The target coverage in each community was >80% of children ages <10 years. Community treatment assistants observed treatment and recorded compliance, thus coverage at the community, household, and individual level could be determined. Within each community, we determined the actual proportions of households where all, some, or none of the children were treated. Assuming the coverage in children <10 years of the community was as observed and non-participation was at random, we did 500 simulations to derive expected proportions of households where all, some, or none of the children were treated. Clustering of household treatment was detected comparing greater-than-expected proportions of households where none or all of children were treated, and the intraclass correlation (ICC) was calculated. Tanzanian and Gambian mass treatment coverages for children <10 years of age ranged from 82-100% and 62-99%, respectively. Clustering of households where all children were treated or no children were treated was greater than expected. Compared to model simulations, all Tanzanian communities and 44 of 48 (91.7%) Gambian communities had significantly higher proportions of households where all children were treated. Furthermore, 30 of 32 (93.8%) Tanzanian communities and 34 of 48 (70.8%) Gambian communities had a significantly elevated proportion of households compared to the expected proportion where no children were treated. The ICC for Tanzania was 0.77 (95% CI 0.74-0.81) and for The Gambia was 0.55 (95% CI 0.51-0.59)., Conclusions/significance: In programs aiming for high coverage, complete compliance or non-compliance with mass treatment clusters within households. Non-compliance cannot be assumed to be at random.