A Cluster-Randomized Trial to Assess the Efficacy of Targeting Trachoma Treatment to Children

Background.: The World Health Organization recommends annual treatment of entire trachoma-endemic communities, although children typically have a higher load, longer duration, and greater likelihood of infection. Methods.: Forty-eight communities in Matameye, Niger, were randomized to annual oral azithromycin treatment of the entire community or biannual treatment of children aged 0-12 years only. Both children and adults were monitored for ocular chlamydial infection by polymerase chain reaction. Results.: The prevalence of childhood infection was reduced in the annually treated arm from 21.2% (95% confidence interval [CI], 15.2%-28.0%) at baseline to 5.8% (95% CI, 3.2%-9.0%) at 36 months (P <. 001) and in the biannual arm from 20.2% (95% CI, 15.5%-25.3%) to 3.8% (95% CI, 2.2%-6.0%; P <. 001). Adult infection in the annual arm was reduced from 1.7% (95% CI,. 9%-2.7%) to 0.3% (95% CI,. 0%-.7%) and in the biannual arm from 1.2% (95% CI,. 5%-2.2%) to 0.0% (95% CI,. 0%-.7%; P =. 005). The effect of biannual treatment of children compared with annual treatment of the entire community in both children (95% CI, -.04% to. 02%) and adults (95% CI,. 9%-2.7%) excluded the prespecified noninferiority threshold of 6% (P =. 003 and P <. 001, respectively). Conclusions.: Periodic distribution of antibiotics to children in trachoma-endemic communities reduces chlamydial infection in both children and untreated adults, suggesting a form of herd protection. Biannual treatment of children was comparable to (specifically, noninferior to) annual treatment of the entire community, and may offer lower antibiotic use and other logistical advantages. Clinical Trials Registration.: NCT00792922.