This study examines health insurance coverage and utilization patterns among Senegalese youth following the introduction of a national health insurance scheme in Sierra Leone. A mixed-methods approach incorporating quantitative survey data and qualitative interviews was employed. A logistic regression model was used to analyse the association between socio-economic factors and coverage uptake. The analysis revealed a significant increase in health insurance coverage from 30% pre-scheme to 52% post-introduction, with urban residents showing higher uptake compared to rural areas (p < 0.05). The national health insurance scheme has effectively increased health insurance coverage among Senegalese youth in Sierra Leone, though disparities remain between urban and rural populations. Further targeted interventions are recommended to address the lower uptake rates in rural areas. Treatment effect was estimated with $\text{logit}(p_i)=\beta_0+\beta^\top X_i$, and uncertainty reported using confidence-interval based inference.