Prospective Cohort Study Finds Malaria Drives 54% of Admissions and Half of In-Hospital Deaths in Sierra Leonean Infants

The ICARIA project combined facility surveillance with household visits, phone follow-up, and community informants to capture admissions and deaths in children under two. Malaria accounted for more than half of severe illness episodes, ahead of lower respiratory infections (16.7%) and diarrhea (9.6%). Full EPI vaccination reduced overall mortality risk by 35% and post-discharge death by 44%, while complete sulfadoxine-pyrimethamine dosing lowered risk by 40%.

Sierra Leone already provides free care under five, seasonal malaria chemoprevention, pneumococcal vaccine, and the RTS,S malaria vaccine, yet progress on under-five mortality has stalled since 2015. The study shows that routine surveillance aggregating all children under five masks the concentrated burden in the first two years and underestimates malaria deaths occurring outside facilities via verbal autopsy.

Undernutrition independently raised in-hospital death risk, highlighting the need to integrate nutrition into malaria and immunization programs. Community-based care and post-discharge follow-up remain weak points.

Next steps require district-level monitoring of malaria vaccine coverage and impact on admissions by 2027, plus trials integrating nutritional support with chemoprevention.