Direct and indirect protection against scabies through ivermectin mass drug administration designed for malaria in...

Ivermectin is an endectocide effective against scabies that is under evaluation as a malaria vector control tool. During the BOHEMIA malaria trial, we did a substudy with the aim of assessing the efficacy of ivermectin mass drug administration (MDA) against scabies.

The BOHEMIA trial was an open-label, assessor-masked, cluster-randomised trial done in a malaria and scabies co-endemic community in Mozambique. Clusters were randomised (1:1:1) to receive a single dose of either ivermectin 400 μg/kg to all eligible humans, 400 μg/kg to humans and 200 μg/kg to eligible livestock, or 400 mg albendazole in humans only (control) for 3 consecutive months. In this scabies substudy, 39 clusters were randomly selected from the main trial. The primary endpoint was scabies prevalence at 3 months. Secondary endpoints were scabies prevalence in directly exposed participants (those who took the study drug) at 1, 2, and 3 months, and indirectly exposed children younger than 5 years (who were living in clusters but did not take the study drug) at 3 and 6 months. An intention-to-treat analysis was done by use of a logistic regression model with a generalised estimating equation approach. This study is registered with ClinicalTrials.gov, NCT04966702, and on the Pan African Clinical Trial Registry, PACTR202106695877303, and is complete.

Recruitment started on March 15, 2022 and was completed on July 6, 2022. Of 40 524 participants from 100 clusters accessed in the BOHEMIA trial, 1951 participants were enrolled from 39 clusters (13 per group) in the scabies substudy. Scabies prevalence in the ivermectin group was lower after 3 months (2·11%, 95% CI 1·21-3·41) than at baseline (8·10%, 6·36-9·85), whereas it did not change in the albendazole group (13·71%, 10·81-17·05, at 3 months vs 12·30%, 9·43-15·17, at baseline). The odds of having scabies was lower in pooled ivermectin clusters than in albendazole clusters after 3 months (adjusted odds ratio [aOR] 0·18, 95% CI 0·07-0·45, p=0·0002). This effect was observed both in directly exposed participants who took ivermectin after 1 month (aOR 0·27, 95% CI 0·11-0·66, p=0·0023), 2 months (0·18, 0·07-0·47, p=0·0006), and 3 months (0·16, 0·06-0·45, p=0·0004), and in indirectly exposed children after 3 months (0·17, 0·05-0·58, p=0·0048) and 6 months (0·21, 0·06-0·72, p=0·013). There were two severe adverse events; both were deaths in the ivermectin group that were not considered related to the study drug. No safety signal was detected.

Ivermectin MDA designed for malaria might have significant benefits against scabies. In addition to directly exposed participants, our results also suggested an effect in indirectly exposed participants, which might reflect a community benefit.

Unitaid.