Inequity in the transmission of malaria infection among children and adolescents: a cohort study in rural Guinea.

Malaria remains a major health concern in rural Guinea, where children face fivefold higher infection risk compared to urban areas. While disparities between rural and urban regions have been documented, inequities within rural areas remain unexplored. Socioeconomic factors influence malaria risk, which varies according to season. Understanding seasonal variations in socioeconomic factors is crucial for developing equitable and targeted interventions. This cohort study was conducted in Mafèrinyah, Guinea, with participants aged 1-19 years of age. Data were collected through monthly home visits over nine months, capturing malaria infection (via blood smears), sociodemographic factors, and household characteristics. Equity analysis was guided by the PROGRESS (place of residence, race/ethnicity/culture/language, occupation, gender/sex, religion, education, socioeconomic status, and social capital) framework. Statistical analyses included concentration index (CI) calculations to assess socioeconomic-related inequality across dry and rainy seasons, binary mixed-effects logistic, and decomposition of CI to identify contributing factors. Malaria infection varies according to season, age, and household characteristics. Children in households with older heads (50-77 years) had higher malaria odds during the dry season (OR = 3.44), whereas adolescents in the rainy season were more vulnerable in middle-aged-headed (OR = 15.78) and single-parent households (OR = 4.52). Concentration indices showed modest pro-rich inequity among adolescents in both seasons (CI = 0.059-0.085) and mixed patterns among children. Among children, secondary education (246.8%) and older age of household head yield strong malaria prevention dividends, but these benefits are currently captured by the better off, while primary education had strong pro-poor effects (among poorer households whose heads had only primary education). Among adolescents, middle-aged heads and older heads (- 419.3%), and unemployment (- 184.2%) reduced inequity. Male-headed households reversed roles by season, contributing - 67.2% to inequity in the dry season and + 19.5% in the rainy season. This study revealed significant seasonal and socioeconomic disparities in malaria transmission among children and adolescents in rural Guinea. Key equity drivers include the household head's age, education, gender, and occupation, which have distinct seasonal effects. These findings highlight the need for targeted, equity-sensitive interventions that address structural vulnerabilities and seasonal dynamics to reduce the malaria burden and promote health equity.