Assessing the Risk of Urinary Tract Infection and Invasive Bacterial Infection in Febrile Infants Aged 7-90 Days With COVID-19.

Introduction Concomitant urinary tract infection (UTI) or invasive bacterial infection (IBI) in previously healthy, well-appearing febrile infants with COVID-19 is low. We sought to review the rates of UTI and IBI in all febrile infants with COVID-19 presenting to community emergency departments (EDs). Methods We retrospectively reviewed infants aged 7-90 days with COVID-19 from July 1, 2020, to August 31, 2022, who had an ED visit. Infants without fever or with COVID-19 more than seven days prior to the index ED visit were excluded. We collected data on blood, urine, and cerebrospinal fluid (CSF) culture results. UTI, bacteremia, and bacterial meningitis were defined by culture review as per prior standards. Results We included 622 infants, of whom 329 were febrile. Older infants and those presenting later in the pandemic had lower rates of complete evaluation. Of the 201 infants with urine collected, four (2%) had a UTI. Of the 184 infants with blood cultures obtained, 19 (10.3%) had contaminated blood cultures. One of the 159 infants (0.6%) with both blood and urine collected had an  bacteremic UTI. Only 12 infants had CSF obtained; however, no infants received treatment for bacterial meningitis. Factors associated with UTI were higher white blood cell (p=0.001) and absolute neutrophil counts (p=0.036), and abnormal urinalysis (UA) and urine microscopy (p<0.001). Conclusions Febrile infants with COVID-19 are at low risk for UTI and even lower risk for IBI. We recommend, at a minimum, that all febrile well-appearing infants aged 7-60 days with COVID-19 be evaluated for concomitant bacterial infections with a UA with microscopy.