Mass Azithromycin Distribution and Community Microbiome: A Cluster-Randomized Trial.

Area of Science:

• Microbiome research
• Public health interventions
• Pediatric infectious diseases

Background:

• Mass azithromycin distribution is used for trachoma elimination and proposed for reducing childhood mortality.
• Observed benefits increase with treatment frequency, suggesting community-level effects.
• This study investigates the impact of biannual mass azithromycin treatments on the gut microbiome in preschool children.

Purpose of the Study:

• To assess the effect of two biannual mass azithromycin treatments on the community's gut microbiome.
• To evaluate long-term alterations in gut microbial structure and diversity 6 months post-treatment.

Main Methods:

• Cluster-randomized controlled trial in Niger involving children aged 1-60 months.
• Randomization at the village level to receive azithromycin or placebo every 6 months.
• Fecal sample analysis using metagenomic deep sequencing; primary outcome: Euclidean PERMANOVA, secondary outcome: Simpson's α diversity.

Main Results:

• Significant differences in gut microbial structures between azithromycin and placebo arms (Euclidean PERMANOVA, P < .001).
• Significantly lower gut microbiome diversity in the azithromycin arm compared to placebo (inverse Simpson's index, P = .005).

Conclusions:

• Two mass azithromycin administrations 6 months apart resulted in long-term alterations to gut microbiome structure and community diversity.
• These microbial alterations were not indicative of disease but were associated with improved childhood mortality.
• The findings support potential community-level benefits of mass azithromycin distribution in children.