92 - Utility of Viral Testing for the Evaluation of Febrile Young Infants without Using Procalcitonin

Poster Number: 92
Publication Number: 92.1519

Background: Febrile infants ≤60 days old are at risk of bacteremia and bacterial meningitis, collectively termed invasive bacterial infections (IBIs). Guidelines from the American Academy of Pediatrics (AAP) recommend that when procalcitonin is unavailable, C-reactive protein (CRP), absolute neutrophil count (ANC) and maximal temperature can be used to identify low-risk infants. Timely access to procalcitonin results remains limited in many clinical settings, whereas rapid multiplex viral testing is more available. How viral testing should be incorporated in the evaluation of febrile young infants however is unknown.

Objective: To determine the prevalence of IBI using AAP-recommended combination of CRP, ANC and temperature, among febrile infants with and without laboratory-confirmed viral infections.

Design/Methods: This was a secondary analysis of prospectively collected quality improvement data of all infants ≤60 days old evaluated for fever at an urban tertiary pediatric emergency department (Jan/2018-Dec/2022). All previously healthy, term infants aged 8-60 days with rectal temperatures of ≥38.0◦C and meeting AAP guideline inclusion/exclusion criteria were included for analysis. Standardized clinical and laboratory data were collected for all infants, which included comprehensive nasopharyngeal multiplex viral testing and 30-day follow-up to ascertain for missed IBIs. Infants with CRP≤20.0mg/L, ANC≤5200/mm3 and maximal temperature ≤38.5◦C were classified as low-risk for IBI. Final IBI classification followed AAP guideline definitions. Groups were compared by Fisher’s exact test.

Results: Of 1346 included infants, 1104 (82.0%) were >21 days old, and 777 (57.7%) were boys; 25 (1.9%) had IBIs and 838 (62.3%) were virus-positive. By AAP criteria, 644 (47.8%) were classified as low-risk with no missed cases of IBI, compared to 702 (52.2%) high-risk infants who had an IBI prevalence of 3.56% (p < 0.0001). Among AAP high-risk infants, IBI prevalence was 6.97% (20/287) when no viral infection was detected. Detection of Rhinovirus did not significantly lower risk of IBI among AAP high-risk infants (2.15%, 4/186), whereas those with non-Rhinovirus viral infections had the lowest risk of IBI (1/229, 0.44%; p=0.01).

Conclusion(s): AAP recommendations using CRP, ANC and temperature missed no cases of IBIs, however most infants did not meet low-risk criteria. High-risk infants with non-Rhinovirus viral infections were at lowest risk of IBIs. Targeted use of viral testing for high-risk infants could inform decision-making regarding invasive testing and disposition when evaluating risk of IBI and procalcitonin is unavailable.