Burden of malaria among children aged 5-10 years in the Sahelian area: do we need to adapt seasonal malaria chemoprophylaxis?

BACKGROUND: Despite its Sahelian context, Niger is one of the sub-Saharan countries reporting the highest number of malaria cases. Currently, preventive measures such as seasonal malaria chemoprophylaxis (SMC) target children under the age of five during the rainy season. However, malaria is increasingly affecting older children, even during the dry season. Therefore, strategies need to be adapted. To this end, this study analyzed data from 35 dispensaries across seven provinces in Niger to evaluate the impact of malaria on different age groups according to ecological context.

METHODS: This retrospective study used routine monthly district data from 2018 to 2021. The collected monthly variables were fever, uncomplicated malaria, severe malaria, and deaths, broken down by sex, age group, and region. A forecasting package under R 4.3.3 was used for SARIMA modeling. Multiple linear regression was performed to identify factors associated with malaria.

RESULTS: Malaria transmission was highly seasonal, with an annual peak observed between July and October during the four-year study period. During this peak period, children aged 12 to 59 months accounted for an average of 33.2% of cases, followed by those aged 10 to 14 years (26.0%) and 2 to 11 months (22.6%).Older children (5–14 years) together accounted for over one-third of all cases. Geographic disparities were marked: southern districts bordering irrigated agricultural zones reported the highest incidence (3,000–7,500 cases per month), while savanna and Saharan districts reported fewer than 2,500 cases. The Niamey V district recorded peaks of 11,000 monthly cases. SARIMA projections indicated a likely increase in cases after 2022.

CONCLUSION: The results confirm seasonal malaria transmission, with peaks concentrated between July and October. While children aged 12 to 59 months are the most vulnerable, a significant burden was also observed in older children over five years of age. Additionally, geographical disparities were observed, with higher incidences in southern districts close to irrigated agricultural areas and lower transmission rates in Sahelian and Saharan districts. These trends highlight the importance of expanding interventions beyond the traditionally targeted groups.