Risk of Serious Bacterial Infections in Young Febrile Infants With COVID-19

The purposes of this study were to describe the clinical characteristics of febrile infants younger than 90 days with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infections, to investigate the prevalence of serious bacterial infections (SBIs) in these infants, and to compare the risk of SBI in SARS-CoV-2-positive febrile infants with sex- and age-matched SARS-CoV- 2-negative febrile infants.

This was a retrospective cohort study conducted from March to November 2020 in a tertiary children's hospital. Patients were identified by International Classification of Diseases, 10th Revision codes and included if age was younger than 90 days, a SARS-CoV-2 test was performed, and at least 1 bacterial culture was collected. Positive cases of SARS-CoV-2 were age- and sex-matched to negative controls for analysis. Serious bacterial infection was defined as a urinary tract infection, bacterial enteritis, bacteremia, and/or bacterial meningitis.

Fifty-three SARS-CoV-2-positive infants were identified with a higher rate of respiratory symptoms and lower white blood cell and C-reactive protein values than their SARS-CoV-2 matched controls. The rate of SBI in the SARS-CoV-2-positive infants was 8% compared with 34% in the controls; the most common infections were urinary tract infections (6% vs 23%). There were no cases of bacteremia or bacterial meningitis in the COVID-19 (coronavirus disease 2019) infants and 2 (4%) cases of bacteremia in the controls. The relative risk of any SBI between the 2 groups was 0.22 (95% confidence interval, 0.1-0.6; P ≤ 0.001).

These results suggest that febrile infants younger than 90 days with COVID-19 have lower rates of SBI than their matched SARS-CoV-2-negative controls. These data are consistent with previous studies describing lower risks of SBI in febrile infants with concomitant viral respiratory tract infections.