Targeted antibiotics for trachoma: a cluster-randomized trial.

BACKGROUND Current guidelines recommend community-wide mass azithromycin for trachoma, but a targeted treatment strategy could reduce the volume of antibiotics required. METHODS 48 Ethiopian communities were randomized to mass, targeted, or delayed azithromycin distributions. In the targeted arm, only children aged 6 months to 5 years with evidence of ocular chlamydia received azithromycin, distributed thrice over the following year. The primary outcome was ocular chlamydia at months 12 and 24, comparing the targeted and delayed arms (0-5 year-olds, superiority analysis) and the targeted and mass azithromycin arms (8-12 year-olds, non-inferiority analysis, 10% non-inferiority margin). RESULTS At baseline the mean prevalence of ocular chlamydia in the three arms ranged from 7-9% among 0-5 year-olds and from 3-9% among 8-12 year-olds. Averaged across months 12-24, the mean prevalence of ocular chlamydia among 0-5 year-olds was 16.7% (95%CI 9.0%-24.4%) in the targeted arm and 22.3% (95%CI 11.1%-33.6%) in the delayed arm (P=0.61). The final mean prevalence of ocular chlamydia among 8-12 year-olds was 13.5% (95% CI 7.9%-19.1%) in the targeted arm and 5.5% (95% CI 0.3%-10.7%) in the mass treatment arm (adjusted risk difference 8.5 percentage points [pp] higher in the targeted arm, 95% CI 0.9 pp -16.1 pp higher). CONCLUSIONS Antibiotic treatments targeted to infected pre-school children did not result in significantly less ocular chlamydia infections compared with untreated communities, and did not meet non-inferiority criteria relative to mass azithromycin distributions. Targeted approaches may require treatment of a broader segment of the population in areas with hyperendemic trachoma.