WIP 12 - Rate of neutropenia in infants 8-60 days of age with SARS-CoV-2 versus non SARS-COV 2 viral infections and sequela of serious bacterial infections.

Publication Number: WIP 12.7374

Rhea Palsule, Rady Children's Hospital San Diego, San Diego, CA, United States; Vanessa Tamas, Rady Children's Hospital San Diego, San Diego, CA, United States; Kathryn A. Hollenbach, RCHSD/UCSD, San Diego, CA, United States

Background: Infants < 60 days old who present to the Pediatric ED for evaluation of fever undergo lab testing to assess for possible serious bacterial infections (SBI), including UTIs, bacteremia, and meningitis. Previous studies have demonstrated a reduced rate of SBI in febrile patients with viral illnesses, including RSV and influenza. Viral infections can lead to a redistribution of neutrophils, resulting in a relative neutropenia.

Objective: Compare the rates of neutropenia in infants with SARS-CoV-2 versus non SARS-COV 2 viral infections and the rates of SBI among the two populations.

Design/Methods: Retrospective case-control study at Rady Children’s Hospital San Diego (8/1/2021 to 12/31/2023).

Inclusion Criteria: Infants 8-60 days of age who presented to the Rady Children's Hospital ED for evaluation of fever (temp >/= 38.0 C)
Cases: Infants who tested positive for SARS-COV 2 viral infections by viral PCR testing
Controls: Infants who tested positive for non SARS-COV 2 viral infections or no virus detected on testing

Exclusion criteria: Infants in which the AAP Infant Fever Guideline is not applicable:
-Preterm ( < 37 weeks gestation)
- < 2 weeks of age, perinatal course complicated by maternal fever, infection, and/or antimicrobial use
-Febrile with high suspicion of HSV infection
-Focal bacterial infection
-Clinical bronchiolitis
-Immune compromise
-Congenital or chromosomal abnormalities
-Neonatal course complicated by surgery or infection
-Medically fragile, requiring some form of ongoing therapeutic intervention to sustain life
-Received immunizations within last 48 hours
-Required escalation in level of care (PICU, NICU)
-Prolonged admission (>14 days)

Primary Outcome: Prevalence of neutropenia as determined by ANC < 1000
Secondary outcome: Rates of SBI among infants with SARS-COV 2 and non SARS-COV 2 viral infections

Analysis: T-test for continuous data, ANOVA among subgroups, χ2 or Fisher's exact test for categorical data

Timeline:
-IRB approved Feb 2024
-Chart retrieval Jul 2024
-Data abstraction done by Dec 2024
-Data analysis and poster done by Feb 2025