Disparities in long-lasting insecticidal bed net usage and malaria burden 2 years after a mass distribution campaign in central Côte d’Ivoire: A cross-sectional survey prior to a cluster randomised trial

Identifying and tackling inequities in long-lasting insecticidal bed net (LLIN) coverage and usage is key in reducing malaria burden. This baseline study, prior to an LLIN trial, describes factors associated with LLIN usage and malaria infection prevalence, two years after a mass distribution in Côte d'Ivoire. In July 2023, cross-sectional data were obtained from randomly selected individuals of all ages in each of 33 study clusters, capturing information on socio-economic status, LLIN ownership, usage and results of malaria rapid diagnostic tests. Random-effects multivariable logistic regression analyses were used to assess factors associated with LLIN usage and malaria infection. A total of 1,672 participants were recruited. LLIN ownership and access were 66.3% (95% CI: 59.4-73.2) and 27.8% (95%CI: 22.6-33.1), respectively. LLIN usage was 50.0% (adjusted odds ratio [aOR]: 0.50; 95%CI: 0.34-0.75), 44.3% (aOR: 0.41; 95%CI: 0.26-0.62) and 56.9% (aOR: 0.72; 95%CI: 0.53-0.98) in participants aged, 5-9, 10-14 and ≥15years, respectively, compared to 63.2% in under-fives. LLIN usage was lowest in females aged 10-14 years (41.0%) and highest in under-five males (68.9%). The odds of LLIN usage were lowest in the second (aOR: 0.63; 95%CI: 0.44-0.90) and middle wealth quintile (aOR: 0.69; 95%CI: 0.47-1.00) compared to the poorest quintile (58.2%). Malaria infection prevalence was 41.1% (95%CI: 37.2-45.0). When compared to under-fives with a malaria prevalence of 61.3%, 5-9, 10-14 and ≥15years had 75.0% (aOR: 1.86; 95%CI: 1.24-2.78), 67.0% (aOR:1.18; 95%CI: 0.78-1.80) and 23.0% (aOR: 0.17; 95%CI: 0.12-0.23) malaria prevalence, respectively. Males (75.8%) and females (74.1%) aged 5-9 years had the highest malaria risk. LLIN users had an infection prevalence of 38.5% (aOR: 0.74; 95%CI: 0.58-0.94), compared to 44.3% in non-users. School-based net distributions, malaria education, routine screening and treatment and chemoprophylaxis in schools alongside community sensitization campaigns are recommended to improve protection and reduce infection risk among school-aged children.