Prevalence of scabies and impetigo three years after mass drug administration with ivermectin and azithromycin.

Background. Ivermectin-based mass drug administration has emerged as a promising strategy for the control of scabies and impetigo in settings where the diseases are endemic. Current follow-up data are limited to 12 months for the majority of studies. Longer-term data are vital to inform the sustainability of interventions. Methods. We conducted a prevalence survey for scabies and impetigo in 10 villages in Choiseul Province of the Solomon Islands 36 months after a single round of ivermectin and azithromycin mass drug coadministration. In the primary analysis, we compared the prevalence of scabies and impetigo at 36 months to the prevalence at baseline. Results. At 36 months, the prevalence of scabies was 4.7% (95% confidence interval [CI], 3.6-6.1), which was significantly lower than at baseline (18.7%; relative reduction, 74.9%; 95% CI, 61.5%-87.7%; P < .001). The prevalence of impetigo was 9.6% (95% CI, 8.1%-11.4%), significantly lower than at baseline (24.7%; relative reduction, 61.3%; 95% CI, 38.7%-100%; P < .001). The highest prevalence of scabies was among children aged <5 years (12.5%; adjusted odds ratio, 33.2; 95% CI, 6.6-603.2), and the highest prevalence of impetigo was among children aged 5-9 years (16.4%; adjusted odds ratio, 8.1; 95% CI, 3.6-21.8). Conclusions. There was a sustained impact of a single round of ivermectin and azithromycin mass drug coadministration on the prevalence of scabies and impetigo 3 years after the intervention. Our data provide further support to adopt this intervention as a central component of global scabies control efforts.