Limitations of Comprehensive Respiratory Viral Testing in Managing Young Infants with Fever.

Abstract

To assess whether and when comprehensive respiratory viral testing contributes to risk stratification and management of febrile young infants (FYI). Single-center, retrospective cohort study of hospitalized FYI, aged ≤90 days (born at term) or ≤52 6/7 postmenstrual weeks (born preterm), over a 5-year period. A total of 456 infants with either a positive respiratory viral test result, regardless of diagnostic assay, or a negative respiratory viral test result obtained by comprehensive panel were included in the final analysis. Main outcomes were serious bacterial infection (SBI) rates overall and in specific subsamples, stratified by viral test results. Rates were estimated assuming a binomial distribution, with confidence intervals derived from a normal approximation. Risk ratios with 95% confidence intervals were calculated using uncertainty propagation. Among 456 FYI (mean age 41 days), 70 (15.4%) had SBI, including 6 cases of bacteremia and 1 of meningitis. Infants with a positive viral test result had an SBI rate of 11.9% (42/354), including 2 cases of bacteremia, with significantly lower rates observed only in those testing positive for influenza (6%) and respiratory syncytial virus (4%). Regardless of viral test results, 93% (65/70) of SBI cases had abnormal inflammatory markers or urinalysis. Invasive bacterial infections occurred in both virus-positive (2/354) and virus-negative infants (5/102). Comprehensive respiratory viral testing appears to have limited value for SBI risk stratification in FYI. It does not seem to support clinical decision-making or replace established risk stratification by inflammatory markers and urinalysis. Targeted testing may represent a more appropriate use of resources.