L-citrulline to Improve Adverse Outcomes in Admitted Children (EChiLiBRiST, Clinical Trial 2, Inpatients)

Children admitted to hospital and meeting the study eligibility criteria who are 0-<60 months of age will be eligible for study inclusion, and for initial biomarker screening using the study-designed rapid triaging PoC test, based on the measurement of sTREM-1. Study participants aged 1m-<5 years of age with sTREM-1 values classified as moderate (i.e., "yellow") or high-risk (i.e., "red") in the traffic light risk-stratification system will be randomly allocated (1:1) to receive L-Cit intervention or placebo. All study participants will be followed for 6 months, with study visits at the study hospitals or at home or via phone communication after discharge at day 3, day 5, day 7, day 28, and month 6. The study primary outcome will be "adverse disease outcome", defined as a composite of mortality, incident neurological sequelae, major adverse kidney event at discharge, need for organ support, clinical shock, coma, severe respiratory distress or need for readmission within 28 days after recruitment.

Inclusion criteria

• Enrolled in the initial prognostic screening component.
• Sick children with fever (axillary temperature>37.5ºC) or a history of fever (within the preceding 72h) or with suspected severe disease.
• 1m-<60 months of age.
• With an indication for admission, or having already been admitted to hospital due to their illness.
• With an sTREM-1 PoC result classifying their disease as of "moderate-high risk" ("yellow" or "red") upon study recruitment and within D3.
• Residents in the study area or willing to be contacted and traced during the study duration.
• Willing to sign an informed consent document.
• Willing to undergo and adhere to study procedures as explained in the IC document.

Exclusion criteria

• Admission to hospital for social reasons (and not on account of their disease).
• Children for which informed consent document has not been signed.
• Known allergy or contraindication to any of the study supplements including lactose intolerance or observing a lactose-free diet.
• Concurrent participation in any other clinical trial.
• Patient under NPO or "nothing by mouth" prescription .
• Contraindication for the insertion of a nasogastric tube (NGT) of for the enteral administration of drugs through the NGT in children who cannot tolerate by mouth.
• Critically sick patient whose prognosis is considered by the clinical researcher as fatal outcome in the following hours after screening.
• Any other condition determined by the investigators that makes it unlikely that the participant would complete the follow up until day 28 of study.