The Immediate Effects of a Combined Mass Drug Administration and Indoor Residual Spraying Campaign to Accelerate Progress towards Malaria Elimination in Grande-Anse, Haiti.

BACKGROUND: Haiti is planning targeted interventions to accelerate progress towards malaria elimination. In the most affected Department (Grande-Anse), a combined mass drug administration (MDA) and indoor residual spraying (IRS) campaign was launched in October 2018. This study assessed the intervention effectiveness in reducing P. falciparum prevalence.

METHODS: An ecological quasi-experimental study was designed, using a pre- and post-test with nonrandomized control group. Surveys were conducted in November 2017 in a panel of easy access groups (25 schools and 16 clinics), and were repeated 2-6 weeks after the campaign, in November 2018. Single-dose sulfadoxine-pyrimethamine and primaquine was used for MDA, and primiphos methyl as insecticide for IRS.

RESULTS: A total of 10,006 participants were recruited. 52% of the population in the intervention area reported having received MDA. Prevalence diminished between 2017 and 2018 in both areas, but the reduction was significantly larger in the intervention area (ratio of adjusted risk ratios = 0.32, 95% confidence interval [0.104 - 0.998]).

CONCLUSIONS: Despite a moderate coverage, the campaign was effective in reducing P. falciparum prevalence immediately after one round. Targeted MDA+IRS are useful in pre-elimination settings to rapidly decrease the parasite reservoir, an encouraging step to accelerate progress towards malaria elimination.