LAUSR

Objectives Widespread Haemophilus influenzae and Streptococcus pneumoniae immunization has decreased occult bacteremia and bacterial meningitis rates. Practice has evolved in pediatric emergency departments (PEDs) to favor fewer diagnostic tests for and empiric treatment of invasive bacterial infection. We lack evidence-based guidance on evaluation and treatment of unimmunized (UnI) or underimmunized (UnderI) febrile children. This study aims to determine how parental report of immunization status in febrile PED patients impacts rates of diagnostic testing, interventions, and hospital admissions. Methods This is a retrospective cohort study with chart review of encounters of children aged 3 to 36 months presenting to an academic, tertiary care PED in 2019 using International Classification of Diseases-10 code for fever (R50.9). Inclusion criteria were documented fever of 38°C and higher and well appearance. Encounters were excluded if there was a history of chronic illness or documentation of ill appearance or hemodynamic instability. Encounters were grouped by provider-documented immunization status. Fischer exact test and logistic regression compared rates of diagnostic testing (serum, urine or cerebrospinal fluid laboratory studies, and chest radiographs), interventions (intravenous fluid bolus, intravenous antibiotic or steroid administration, respiratory support, or breathing treatment), and hospital admissions between UnderI, UnI, and fully immunized (FI) groups. Results Of the 1813 encounters reviewed, 1093 (60%) included provider-documented immunization status and 788 (43%) met final inclusion criteria: 23 (2.1%) UnI, 44 (5.8%) UnderI, and 721 (92.1%) FI. The UnderI and UnI children experienced significantly higher rates of laboratory evaluation including complete blood count and blood culture, medical intervention, and antibiotic prescriptions while in the PED. No significant differences were observed for rates of chest radiographs, hospital admissions, or 72-hour PED return visits. Conclusions Higher rates of laboratory testing and interventions were observed in UnderI and UnI versus FI febrile patients at a PED, likely demonstrating increased clinical suspicion for invasive bacterial infection in this group despite lacking national guidelines. Given continued vaccine hesitancy, further studies are needed for guiding management of febrile UnI and UnderI children presenting for emergency care.