Inclusion Criteria:  Age 30 days to less than 1 year Chief complaint of Apnea, BRUE, Fussiness or Irritability, Lethargy, Neurologic complaint, Poor Feeding-Acute, Seizures/Spells, or Vomiting Alone First temperature in the ED less than or equal to 38.3C Acuity level/ESI of 3, 4, or 5  Exclusion Criteria:  History of trauma related to this ED encounter Parent reported temperature of greater than 38.3C in the prior 24 hours Prior abnormal neuroimaging Previously enrolled in this study within preceding 28 days Provider preference for any reason