Azithromycin in control of trachoma

Abstract

Background: Trachoma is the leading cause of preventable blindness. Programmes to prevent blindness due to trachoma are based on community-wide treatment with topical tetracycline. We assessed the potential of community-wide azithromycin treatment for trachoma control. Methods: Pairs of villages in trachoma endemic areas of Egypt, The Gambia, and Tanzania were matched on trachoma rates in 1-10-year-old children. Villages were randomly assigned community-wide oral azithromycin treatment (three doses with intervals of 1 week) or treatment with 1% topical tetracycline (once daily for 6 weeks). Clinical examinations were done at baseline, 2-4.5 months, and 12-14 months after treatment. Chlamydia trachomatitis was identified by ligase chain reaction (LCR). Analyses were by intention to treat. Univariate comparisons and multivariate analyses were used to compare outcomes. Findings: LCR positivity was correlated with clinical severity, but about 30% of Egyptian and Gambian villagers with no active disease were LCR positive. Village-wide LCR positivity ranged from 16.5% (Tanzania) to 43.6% (Egypt). Treatment compliance was over 90% except in the tetracycline treatment village in Egypt. Of the participants initially LCR positive, 866 (95%) of 924 who received at least one azithromycin dose and 482 (82%) of 587 who received 28 days or more topical tetracycline, were negative at follow-up. At 1 year, village-wide LCR positivity rates were substantially lower than at baseline with both treatments; the decreases were greater with azithromycin than with tetracycline (93% vs 77% in Egypt, 78 vs 66% in The Gambia, 64 vs 55% in Tanzania). Similarly, greater reduction in clinical activity occurred after azithromycin. In multivariate analyses, factors associated with being LCR positive at 1 year were: not receiving azithromycin; age under 10 years; and LCR positivity at baseline. Interpretation: Community-wide treatment with oral azithromycin markedly reduces C trachomatis infection and clinical trachoma in endemic areas and may be an important approach to control of trachoma.