Insufficient Ratio of Long-Lasting Insecticidal Nets to Household Members Limited Universal Usage in Western Kenya: A 2015 Cross-Sectional Study.

Universal "coverage" with long-lasting insecticidal nets (LLINs) is recommended for malaria control in endemic areas, but ownership does not ensure usage. We evaluated relationships between household-level ownership and individual-level usage in western Kenya in 2015. Low-prevalence highland (> 1,500 m) and highly endemic lowland (< 1,200 m) sites were surveyed from July to August 2015. Household members reported long-lasting insecticidal net ownership, use, and barriers to use. Net ownership was categorized as sufficient (≤ 2 people/net), insufficient (> 2 people/net), or none. Each LLIN was assumed to provide access to two people. We surveyed 574 lowland and 643 highland households, with 1,677 and 2,742 members, respectively. More than 98% of lowland households owned LLIN(s); 72.1% owned a sufficient number. Only 37.5% of highland households had sufficient nets. More people used LLINs than were estimated to have access in the lowlands (94.2% versus 85.3%), but proportions were similar in the highlands (54.3% versus 53.3%). Insufficient ownership was most common for larger households in both areas and strongly predicted LLIN usage. In households with insufficient nets, men, school-age children (aged 5-15 years), and nonnuclear family members were less likely to use LLINs; only relationship to the head of the household significantly predicted use in households with sufficient nets. Long-lasting insecticidal nets were widespread in western Kenya in 2015, but insufficient household ownership remained common in the epidemic highlands and in large households. Access seemed to be the primary driver of individual use. To interrupt transmission, LLIN campaigns should improve distribution to large households and promote use among men, school-age children, and nonnuclear family members.