A Randomized Trial of Two Coverage Targets for Mass Treatment with Azithromycin for Trachoma

Sheila K West,Thomas Lietman,David Mabey,Thomas C Quinn,Tansy Edwards,Charlotte Gaydos,Robin Bailey,Travis Porco,Beatriz Munoz,Harran Mkocha

doi:10.1371/journal.pntd.0002415

Abstract

BackgroundThe World Health Organization recommends at least 3 annual antibiotic mass drug administrations (MDA) where the prevalence of trachoma is >10% in children ages 1–9 years, with coverage at least at 80%. However, the additional value of higher coverage targeted at children with multiple rounds is unknown.Trial Design2×2 factorial community randomized, double blind, trial.Trial methods32 communities with prevalence of trachoma ≥20% were randomized to: annual MDA aiming for coverage of children between 80%–90% (usual target) versus aiming for coverage>90% (enhanced target); and to: MDA for three years versus a rule of cessation of MDA early if the estimated prevalence of ocular C. trachomatis infection was less than 5%. The primary outcome was the community prevalence of infection with C. trachomatis at 36 months.ResultsOver the trial's course, no community met the MDA cessation rule, so all communities had the full 3 rounds of MDA. At 36 months, there was no significant difference in the prevalence of infection, 4.0 versus 5.4 (mean adjusted difference = 1.4%, 95% CI = −1.0% to 3.8%), nor in the prevalence of trachoma, 6.1 versus 9.0 (mean adjusted difference = 2.6%, 95% CI = −0.3% to 5.3%) comparing the usual target to the enhanced target group. There was no difference if analyzed using coverage as a continuous variable.ConclusionIn communities that had pre-treatment prevalence of follicular trachoma of 20% or greater, there is no evidence that MDA can be stopped before 3 annual rounds, even with high coverage. Increasing coverage in children above 90% does not appear to confer additional benefit.

Highlights

Trachoma, caused by ocular Chlamydia trachomatis, is the leading infectious cause of blindness world-wide [1]
In communities that had pre-treatment prevalence of follicular trachoma of 20% or greater, there is no evidence that mass drug administrations (MDA) can be stopped before 3 annual rounds, even with high coverage
A multi-faceted strategy to control all phases of trachoma has been endorsed by the World Health Organization (WHO), consisting of Surgery (to repair lids distorted by trachoma in imminent danger of vision loss), Antibiotics (mass drug treatment (MDA) to reduce the community pool of infection with Chlamydia trachomatis), Face washing, and Environmental improvements

Summary

Introduction

Trachoma, caused by ocular Chlamydia trachomatis, is the leading infectious cause of blindness world-wide [1]. A multi-faceted strategy to control all phases of trachoma has been endorsed by the World Health Organization (WHO), consisting of Surgery (to repair lids distorted by trachoma (trichiasis) in imminent danger of vision loss), Antibiotics (mass drug (antibiotic) treatment (MDA) to reduce the community pool of infection with Chlamydia trachomatis), Face washing (to reduce transmission from ocular and nasal secretions), and Environmental improvements (to interrupt transmission and prevent re-emergence). The World Health Organization recommends at least 3 annual antibiotic mass drug administrations (MDA) where the prevalence of trachoma is .10% in children ages 1–9 years, with coverage at least at 80%. Trial methods: 32 communities with prevalence of trachoma $20% were randomized to: annual MDA aiming for coverage of children between 80%–90% (usual target) versus aiming for coverage.90% (enhanced target); and to: MDA for three years versus a rule of cessation of MDA early if the estimated prevalence of ocular C. trachomatis infection was less than 5%. The primary outcome was the community prevalence of infection with C. trachomatis at 36 months

Methods

Results

Conclusion