Urinary tract infection must be excluded in infants less than 3 months of age with fever and respiratory syncytial virus (RSV).

Prevalence of significant bacterial infections in young infants who have RSV is unknown. Prospective evaluations of all infants <3 months old who had a sepsis evaluation for fever and an RSV antigen test: 128 infants, 50 (39%) were RSV (+) and 78 (61%) infants were RSV (-). Median age in the RSV (+) group was 44.3 [+ or -] 19.4 and RSV (-) 43.6 [+ or -] 19.2 days old. There were more URI symptoms and coughing in the RSV (+) group (P < 0.05). The number admitted in RSV (+) group was 38 (76%) versus 62 (79.4%) in RSV (-). There were 6 (12%) infants admitted to the PICU in the RSV (+) group versus 1 (1.2%) in the RSV (-). Laboratory evaluation in the RSV (+) included a CBC 46 (92%), urinalysis and culture 44 (88%), blood culture 45 (90%), chest radiograph 21 (62%) and CSF fluid analysis 22 (44%). In the RSV (-) the laboratory evaluation included a CBC 71 (91%), urinalysis and urine culture 71 (91%), blood culture 73 (93.5%), chest radiograph 36 (46.1%) and CSF fluid analysis 53 (67.9%). There was more chest radiographs performed in the RSV (+) group (P < 0.05). There were 7(14%) significant infections in the RSV (+) group versus 8 (10.2%) in the RSV (-) group. In the RSV (+) group there were 5 (10%) pneumonias, 1 (2%) UTI. In the RSV (-) group here were 4 (5.1%) pneumonias, 3 (2.5%) UTI, 1 (1.2%) bacteremia with group B streptococcus, and 1 (1.2%) meningitis with enterococcus. The risk of serious bacterial infection is low in the RSV (+) group, especially if exclude the pneumonias. There were no cases of bacteremia or meningitis, however UTI still are significant. It may be prudent to exclude UTI in febrile infants with RSV (+).

Antonio E. Muniz, MD. Department of Emergency Medicine and Pediatrics, Virginia Commonwealth University Medical Center, Richmond, VA.