Effects of Targeted Antibiotics to Eliminate Community-Wide Trachoma

Among preschool-aged children with ocular chlamydia, targeted antibiotic treatment did not provide a significant community-wide benefit for trachoma prevention, according to study results published in Clinical Infectious Diseases.

In its trachoma elimination strategy, the World Health Organization provides an annual community-wide antibiotic distribution. As preschool-aged children have a higher prevalence of trachoma, higher infection loads, and longer durations of infection, this demographic is likely responsible for most transmission.

To determine whether targeted antibiotic treatments could prevent community transmission of ocular strains of chlamydia that cause trachoma, a team of investigators conducted a cluster-randomized trial. The Targeted Antibiotic Intervention for Trachoma in Under-Fives (TAITU) trial was conducted in 48 Ethiopian communities from November 2015 to March 2018.

Investigators randomly assigned communities to 1 of 3 study arms: annual mass drug administration (MDA) of azithromycin to the entire community, targeted triannual azithromycin treatments directed to children age 0 to 5 years with ocular chlamydia, and delayed treatment. The primary outcome of the study was chlamydia infection, assessed at 12 and 24 months after baseline in children aged 0 to 5 years and children aged 8 to 12 years.

The 3 arms had similar prevalence of ocular chlamydia at baseline, with mean prevalence ranging from 7.8% to 9.3% for children aged 0 to 5 years, and 3.0% to 8.6% for children aged 8 to 12 years.

In the MDA arm, all communities reached at least 80% coverage during both years of the analysis. In the targeted treatment arm, all children who tested positive for ocular chlamydia at baseline, as well as 97% of children who tested positive at 12 months, were administered all 3 azithromycin treatments.

Averaged over months 12 and 24 follow-up visits, the mean prevalence of ocular chlamydia in children aged 0 to 5 years was 22.3% in the delayed treatment arm and 16.7% in the targeted treatment arm. Although the targeted treatment arm had fewer infections detected compared with the delayed treatment arm, the difference was not statistically significant (P =.61).

Among children aged 8 to 12 years, the mean prevalence of ocular chlamydia at 24 months was 5.5% in the MDA arm and 13.5% in the targeted triannual treatment arm.

The authors noted that the study area had received repeated rounds of mass azithromycin treatment for 7 years before the present analysis, and still the prevalence of ocular chlamydia was high at this study baseline. Further, infection increased throughout the duration of the analysis in both monitored age groups.

“An intervention more intensive than the status quo of annual mass azithromycin distributions is likely to be necessary for controlling trachoma in areas with a high prevalence of disease,” the investigators concluded.

Reference

Melo JS, Aragie S, Chernet A, et al. Targeted antibiotics for trachoma: a cluster-randomized trial. Clin Infect Dis. Published online March 1, 2021. doi:10.1093/cid/ciab193