Inclusion Criteria:

1. The patient and/or where relevant their parent/guardian/caretaker is willing and able to give informed consent /assent for participation in the study;
2. Aged > 28 days (day of birth = Day 1);
3. Axillary temperature at presentation (≥ 37.5°C (99.5°F) OR < 35.5°C (95.9°F)) and no more likely cause than sepsis for hypothermia OR History of fever in the 24 hours prior to presentation;
4. Onset of illness ≤ 14 days

Exclusion Criteria:

1. Accident or trauma is the cause for the patient's presentation;
2. Presentation ≤ 3 days after routine immunisations
3. Is currently under follow-up or has been afebrile for less than 72 hours after completion of a follow-up period.
4. The treating healthcare worker's decision is to send the patient home following initial assessment.