Evaluation of two delivery strategies to improve coverage and adherence to Seasonal Malaria Chemoprevention (SMC) in Mali

Seasonal Malaria Chemoprevention (SMC) involves a 3-day regimen of sulfadoxine-pyrimethamine plus amodiaquine administered to children once a month during the high malaria season. WHO guidelines recommend that SMC distributors administer or observe treatment on the first day and leave the remaining doses for caregivers to administer (“standard SMC”). In some countries distributors return on day 2 and again on day 3 so that all doses can be directly observed (“3-day DOT”), but there is little evidence that the additional costs are justified. We investigated whether 3-day DOT improves SMC coverage and adherence, and reduces malaria incidence, compared to standard SMC, and whether a modified strategy, whereby standard SMC is supplemented using local community volunteers who are trained to follow-up on days 2 and 3 (“community SMC”, cSMC), is as effective as 3-day DOT. Each of the three strategies was implemented in 2 health areas over 4 months from July to October 2022 in Dioila health district in the Koulikoro region of Mali. The coverage of SMC (the percentage of children receiving at least the first daily dose in each of the 4 months), and adherence to the 3-day regimen in the last month, were assessed in household surveys after the last monthly cycle. Attitudes to the delivery strategies were explored through focus groups with caregivers, and key informant interviews. Malaria incidence was monitored through passive case detection at health centres in each area, and costs of the additional staff time required for 3-day DOT, and for the local volunteers for cSMC, were estimated. Caregivers and health staff expressed positive attitudes to SMC, and to the cSMC strategy, but mentioned concerns about adherence using the standard approach. These concerns were not reflected in the reported adherence to the 3-day regimen which was very high in all three intervention zones: among children who received the first dose, 98.2% (95% confidence interval (CI) 93.0–99.6%) received the second and third dose of amodiaquine in the standard SMC strategy, according to caregivers; 99.7% (95% CI 97.1–100.0%), in the 3-day DOTs strategy; and 100% (95% CI 98.8–100.0%) with the community SMC strategy. There was no evidence that 3-day DOT or the community strategy improved adherence compared to standard SMC. SMC coverage (the proportion of children receiving at least the first dose for all four cycles) however was higher with the community strategy than standard SMC. The proportion of children receiving at least the first dose for all 4 cycles was 84.6% for standard SMC, 95.2% for 3-day DOT (coverage difference 10.6%, 95% CI − 5.9, 27.2, compared to standard) and 99.1% for cSMC (coverage difference compared to standard SMC 14.5%, 95% CI 0.4%, 28.5%, and compared to 3-day DOT, 3.8%, 95% CI − 5.1, 12.8). Incidence rate ratios for clinical malaria during the 4 months of intervention were 0.77 (95% CI 0.20, 2.87) for 3-day DOT compared to standard SMC, 0.79 (0.38, 1.67) for cSMC compared to standard SMC, and 1.03 (0.38, 2.84) for cSMC compared to 3-day DOT. The additional cost required for 3-day DOT was 0.25$ per child per cycle, and 0.20$ for cSMC. Adherence as reported by caregivers was very high with standard SMC and not improved when doses on days 2 and 3 were supervised by distributors or local volunteers. However, SMC coverage, the percentage of children receiving at least the first dose in all four months, was higher with the community strategy than standard SMC. Our findings do not support the use of 3-day DOT to improve adherence. Strategies to identify children who missed SMC on the first day, such as the community approach, can improve coverage at lower cost than 3-day DOT. The emphasis should be on reaching all children with the first dose of SMC each month rather than daily visits to montor adherence.