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

ABSTRACT

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 TF_1-9 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 TF_1-9 is between 5 and 9.9% at baseline.

KEYWORDS:

• Antibody
• chlamydia
• mass drug administration
• trachoma
• trachomatis

Acknowledgments

The findings and conclusions in this report are those of the authors and do not necessarily represent the official position of the U.S. Centers for Disease Control and Prevention.

The authors would like to thank all study participants. The authors would like to acknowledge the hard work of the Kongwa Trachoma Project staff. We appreciate the support of the National Institute of Medical Research and the Kongwa District Medical Officer for this study. We would like to thank Sonia Pelletreau, Kim Won, and Paul Cantey for helpful discussions in the planning of this project. We would also like to thank Maurice Odiere and Fred Rawango for assistance in training KTP staff to undertake this project.

Declaration of interest

The authors report no conflict of interest. The authors alone are responsible for the writing and content of this article.

Funding

Funding for this project was provided by the Bill and Melinda Gates Foundation (project OPP1022543).

Additional information

Funding

Funding for this project was provided by the Bill and Melinda Gates Foundation (project OPP1022543).