Stopping azithromycin mass drug administration for trachoma: A systematic review

Abstract

The World Health Organization (WHO) recommends continuing azithromycin mass drug administration (MDA) for trachoma until endemic regions drop below 5% prevalence of active trachoma in children aged 1-9 years. Azithromycin targets the ocular strains of Chlamydia trachomatis that cause trachoma. Regions with low prevalence of active trachoma may have little if any ocular chlamydia, and, thus, may not benefit from azithromycin treatment. Understanding what happens to active trachoma and ocular chlamydia prevalence after stopping azithromycin MDA may improve future treatment decisions. We systematically reviewed published evidence for community prevalence of both active trachoma and ocular chlamydia after cessation of azithromycin distribution. We searched electronic databases for all peer-reviewed studies published before May 2020 that included at least 2 post-MDA surveillance surveys of ocular chlamydia and/or the active trachoma marker, trachomatous inflammation-follicular (TF) prevalence. We assessed trends in the prevalence of both indicators over time after stopping azithromycin MDA. Of 140 identified studies, 21 met inclusion criteria and were used for qualitative synthesis. Post-MDA, we found a gradual increase in ocular chlamydia infection prevalence over time, while TF prevalence generally gradually declined. Ocular chlamydia infection may be a better measurement tool compared to TF for detecting trachoma recrudescence in communities after stopping azithromycin MDA. These findings may guide future trachoma treatment and surveillance efforts.

Fig 1. Flow diagram of the study selection process.

ASTMH, American Society for Tropical Medicine and Hygiene.

Fig 2. Prevalence of ocular chlamydia and active trachoma at first and second post-MDA discontinuation time points.

Prevalence of ocular chlamydia (Fig 2A) and TF (Fig 2B) at first and second post-mass distribution administration of azithromycin surveys. The solid black line indicates 45° line. The red dashed line on panel (Fig 2B) indicates the TF control threshold (5%). MDA, mass drug administration; TF, trachomatous inflammation–follicular.

Fig 3. Prevalence of ocular chlamydia and active trachoma post-MDA discontinuation over time.

Prevalence of ocular chlamydia (Fig 3A) and TF (Fig 3B) at each post-mass distribution administration of azithromycin time point (in months). The vertical gray dotted line indicates the first post-MDA time point for each included study. The red dashed line for Fig 3B indicates the 5% TF threshold. MDA, mass drug administration; TF, trachomatous inflammation–follicular.