The burden of malaria in The Gambia has substantially declined over the past two decades. However, the transmission of the disease persists, especially in the eastern part of the country.  The vision of the World Health Organization and the global malaria community is a world free of malaria. Countries can accelerate efforts toward elimination by combining interventions tailored to local contexts.

Researchers at the Medical Research Council Unit The Gambia at the London School of Hygiene & Tropical Medicine (MRCG at LSHTM) conducted the first cluster-randomised trial to assess the combined effect of mass drug administration (MDA) with ivermectin and dihydroartemisinin-piperaquine on the prevalence of Plasmodium falciparum infection and survival of malaria vectors in settings where the coverage of standard control interventions is high.

The trial was conducted in the Upper River Region of The Gambia, an area of highly seasonal malaria with peak transmission between September and November, as well as high vector survival.

Thirty-two villages were enrolled and randomised in 2017 to either the intervention or control group, with a total study population of 10,638 participants.  The intervention, consisting of three monthly rounds of MDA with ivermectin and dihydroartemisinin-piperaquine was implemented in August, September and October in 2018 and in July, August and September in 2019.,

The results of the trial, published in Lancet Infectious Diseases, show that MDA with ivermectin and dihydroartemisinin-piperaquine significantly reduced malaria prevalence and incidence as compared to the control group. Although there was no difference observed in the mosquito population survival, the intervention resulted in significantly lower vector density.

The study, funded by the Joint Global Health Trials Scheme, is the first to show that community MDA with ivermectin and dihydroartemisinin-piperaquine is safe, well-tolerated, and reduces residual malaria transmission in an area with highly seasonal malaria and high coverage of control interventions.

Dr Edgard Dabira, lead author of the publication said, “This was a great experience to coordinate and implement such a big community trial. Achieving high coverage of the intervention was quite challenging. However, engaging the communities and other stakeholders including the Regional Health Directorate, we were able to achieve optimum coverage especially during the second year of the trial implementation.  The results of the trial indicate the potential of the intervention to complement the current malaria control tools”.

Professor Umberto D’Alessandro, Director of the MRCG at LSHTM and Theme Leader for Disease Control & Elimination said, “Although we were unable to show an effect on vector survival at the community level, the mosquito-killing effect of ivermectin at the individual level was evident up to 21 days post-treatment. This study confirms ivermectin as an additional tool for malaria control that should probably be used in combination with other interventions”.

The study provides useful insight into the potential of adding MDA with ivermectin and dihydroartemisinin-piperaquine to the currently available malaria control interventions to accelerate the path towards the WHO elimination agenda by 2030.

Publication

Mass drug administration of ivermectin and dihydroartemisinin–piperaquine against malaria in settings with high coverage of standard control interventions: a cluster-randomised controlled trial in The Gambia. Lancet Infectious Diseases (2021)

DOI: 10.1016/S1473-3099(21)00557-0