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

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 genderand 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. Pediatrics 2003;112:282–284; fever, infants, respiratory syncytial virus, septic evaluations. ABBREVIATIONS. SBI, serious bacterial infection; RSV, respiratory syncytial virus; ED, emergency department; UTI, urinary tract infection; CSF, cerebrospinal fluid; WBC, white blood cell. Fever is a common presenting complaint in the pediatric emergency department. The neonate who presents with fever is a particular challenge, as the clinical evaluation is often difficult and there is a relatively high rate of serious bacterial infection (SBI) in this population. The established evaluation of the neonate with fever generally involves a conservative and invasive workup designed to exclude any SBI. The typical workup includes a complete blood count, blood culture, urinalysis, urine culture, and analysis of spinal fluid with culture.1 In recent years, there have been efforts to define selected populations who may be at low risk for SBI2,3 and might be eligible for a modified evaluation. In particular, it has been believed that neonates with objective evidence of a viral infection may not need the complete septic workup.4–6 Respiratory syncytial virus (RSV) is the leading cause of lower respiratory tract disease in neonates and young children and is responsible for 50% to 90% of hospitalizations for bronchiolitis.7 Patients with RSV infection may present with a variety of symptoms, including upper respiratory congestion, respiratory distress, apnea, and fever. Previous studies have demonstrated that the risk of SBI in infants and children with clinical bronchiolitis is minimal.4– 6,8 Many of the subjects in previous studies, however, were not febrile and most were older than 8 weeks. Despite these studies, clinicians are left with uncertainty regarding the evaluation necessary to exclude SBI in the population of infants who have RSV and are younger than 8 weeks and febrile. 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 genderand age-matched control subjects who were febrile and RSV-negative.