Impact of health facility-based insecticide treated bednet distribution in Malawi: progress and challenges towards achieving universal coverage

Background: High levels of insecticide treated bednet (ITN) use reduce malaria burden in countries with intense transmission such as Malawi. Since 2007 Malawi has implemented free health facility-based ITN distribution for pregnant women and children ,5 years old (under-5s). We evaluated the progress of this targeted approach toward achieving universal ITN coverage. Methods: We conducted a cross-sectional household survey in eight districts in April 2009. We assessed household ITN possession, ITN use by all household members, and P. falciparum asexual parasitemia and anemia (hemoglobin ,11 grams/ deciliter) in under-5s. Results: We surveyed 7,407 households containing 29,806 persons. Fifty-nine percent of all households (95% confidence interval [95% CI]: 56–62), 67% (95% CI: 64–70) of eligible households (i.e., households with pregnant women or under-5s), and 40% (95% CI: 36–45) of ineligible households owned an ITN. In households with at least one ITN, 76% (95% CI: 74–78) of all household members, 88% (95% CI: 87–90) of under-5s and 90% (95% CI: 85–94) of pregnant women used an ITN the previous night. Of 6,677 ITNs, 92% (95% CI: 90–94) were used the previous night with a mean of 2.4 persons sleeping under each ITN. In multivariable models adjusting for district, socioeconomic status and indoor residual spraying use, ITN use by under-5s was associated with a significant reduction in asexual parasitemia (adjusted odds ratio (aOR) 0.79; 95% CI: 0.64– 0.98; p-value 0.03) and anemia (aOR 0.79; 95% CI 0.62–0.99; p-value 0.04). Of potential targeted and non-targeted mass distribution strategies, a campaign distributing 1 ITN per household might increase coverage to 2.1 household members per ITN, and thus achieve near universal coverage often defined as 2 household members per ITN. Conclusions: Malawi has substantially increased ITN coverage using health facility-based distribution targeting pregnant women and under-5s, but needs to supplement these activities with non-targeted mass distribution campaigns to achieve universal coverage and maximum public health impact.