Randomized Trial of High Dose Azithromycin Compared to Standard Dosing for Children with Severe Trachoma in Tanzania

Background: Children with a heavy load of C. trachomatis infection may continue to be infected following a single dose of 20 mg/kg of azithromycin. We compared the C. trachomatis infection rates at six weeks post-treatment of children randomized to 30 mg/kg single dose of azithromycin versus 20 mg/kg single dose of azithromycin. Methods: Ninety-nine children with severe trachoma (defined as either trachoma intense or follicular trachoma with ten or more follicles) were enrolled and randomly assigned. Baseline data on age, sex, and trachoma status was obtained, and swabs for determination of C. trachomatis were taken. Dosing was weight-based and observed. Children were followed up at six weeks for trachoma and infection. The laboratory was masked to treatment assignment. Results: Both groups experienced reductions in infection and in severe trachoma. Twelve percent of the 20 mg/kg group were PCR positive at 6 weeks, compared with 69% at baseline, an 82% reduction (p-value .001). In the 30 mg/kg group, 15% were infected, compared with 62% at baseline, a 76% reduction (p .001). The rate of infection comparing treatment groups was not significantly different at 6 weeks (p = 0.71). Analyses on children who were infected at baseline showed those remaining positive at six weeks were 18%, and 14% in the standard and high dose groups, respectively. Conclusion: Increasing the single dose of azithromycin to 30 mg/kg in children with severe trachoma did not result in significantly less infection at six weeks post-treatment compared to 20 mg/kg.