Retrospective review of serious bacterial infections in infants who are 0 to 36 months of age and have influenza a infection

Objective. Previous studies of febrile children who were 3 to 36 months of age and had clinically recognizable viral syndromes have shown low rates of concurrent bacteremia. We sought to determine the prevalence of serious bacterial infections (SBIs) among children with influenza A, a viral syndrome that can be established definitively by specific tests. Methods. We performed a retrospective cross-sectional study of patients who were 0 to 36 months of age and presented with fever to the emergency department (ED) over 4 consecutive influenza seasons. Chest radiographs and urine and cerebrospinal fluid cultures also were reviewed. Results. Of 705 included patients, 163 (23%) were influenza positive (IP) and 542 (77%) were influenza negative (IN). Only 1 IP patient was bacteremic (0.6%) versus 23 of the 542 IN control subjects (4.2%). Two (1.8%) of 110 IP cases had urinary tract infections versus 38 (9.9%) of the 382 IN control subjects. Thirteen (25.4%) of 51 IP patients had radiographic evidence of pneumonia versus 99 (41.9%) of 236 IN control subjects. There were no cases of meningitis in 41 cerebrospinal fluid samples obtained from IP patients versus 4 (2.2%) cases of culture-positive meningitis in 179 IN control subjects. A total of 16 (9.8%) SBIs were identified in the IP cases versus 153 (28.2%) in the IN control subjects. Conclusions. Febrile children with influenza A had a lower prevalence of bacteremia, urinary tract infections, consolidative pneumonia, or any SBI compared with those without influenza A infection in this study.