An anonymised dataset of 1,955 paediatric and adult patients with febrile illness in southern Mozambique, who gave informed consent to participate in the prospective observational FIEBRE study between December 2018 and February 2021. Dataset contains variables on biomarker levels in plasma, demographic data, results of basic diagnostic tests and health status data, calculated clinical severity scores, and mortality and other adverse outcomes by day 28 follow-up.