Evaluation of a Single Dose of Azithromycin for Trachoma in Low-Prevalence Communities

Evaluation of a Single Dose of Azithromycin for Trachoma in Low-Prevalence Communities


Purpose: Trachoma, caused by repeated ocular infection with Chlamydia trachomatis, is the leading infectious cause of blindness worldwide and is targeted for elimination as a public health problem. We sought to determine whether a one-time azithromycin mass treatment would reduce trachomatous inflammation–follicular (TF) levels below the elimination threshold of 5% in communities with disease prevalence between 5 and 9.9%.

Methods: The study was conducted in 96 sub-village units (balozis) in the Kongwa district of Tanzania which were predicted from prior prevalence surveys to have TF between 5 and 9.9%. Balozis were randomly assigned to the intervention and control arms. The intervention arm received a single mass drug administration of azithromycin. At baseline and 12-month follow-up, ocular exams for trachoma, ocular swabs for detection of chlamydial DNA, and finger prick blood for analysis of anti-chlamydial antibody were taken.

Results: Comparison of baseline and 12-month follow-up showed no significant difference in the overall TF1-9 prevalence by balozi between control and treatment arms. In the treatment arm there was a significant reduction of ocular infection 12 months after treatment (p = 0.004) but no change in the control arm. No change in Pgp3-specific antibody responses were observed after treatment in the control or treatment arms. Anti-CT694 responses increased in both study arms (p = 0.009 for control arm and p = 0.04 for treatment arm).

Conclusion: These data suggest that a single round of MDA may not be sufficient to decrease TF levels below 5% when TF1-9 is between 5 and 9.9% at baseline.

Nana Wilson, Brook Goodhew, Harran Mkocha, Kahaliah Joseph, Claudiu Bandea, Carolyn Black, Joseph Igietseme, Beatriz Munoz, Sheila K. West, Patrick Lammie, Mabula Kasubi & Diana L. Martin. 2019. Ophthalmic Epidemiology; 26(1):1-6. DOI: 10.1080/09286586.2017.1293693