Prevalence of Serious Bacterial Infections in Febrile Infants With Respiratory Syncytial Virus Infection

Abstract

Objective. Neonates with fever generally undergo a full, invasive septic evaluation to exclude serious bacterial infection (SBI). The risk of SBI in febrile older infants and children with documented respiratory syncytial virus (RSV) infection has been found to be negligible. The purpose of this study was to investigate the prevalence of SBI in febrile infants who were younger than 8 weeks and had documented RSV infection and to compare the risk of SBI with control subjects who were febrile and RSV-negative. Methods. This was a retrospective cohort study of infants who were age 8 weeks or less and presented with documented fever to the emergency department at an urban children’s hospital in October through April during a 4-year period. RSV-positive cases were gender- and age-matched to febrile RSV-negative control subjects. Clinical characteristics and the rate of SBI were compared between the 2 groups. Results. A total of 174 previously healthy infants with fever and a positive RSV antigen test were identified and matched with 174 previously healthy infants with fever and a negative RSV test. Infants with RSV infection were more likely to present with upper respiratory infection symptoms, increased work of breathing, and apnea. Overall, 2 patients in the RSV group had SBI (both with urinary tract infections), compared with 22 in the control group (relative risk: 0.009), 17 of which were urinary tract infections. Conclusions. The risk of SBI in febrile infants with RSV infection seems to be very low, particularly in comparison with a control group of RSV-negative infants. These data suggest that full septic evaluations are not necessary in nontoxic-appearing infants with a positive RSV test. It seems to be prudent to examine the urine in these infants, as there is a clinically relevant rate of urinary tract infection.