A Population-Based Study of Rates of Invasive Bacterial Infection (IBI) and Missed IBI in Febrile Infants 8-90 Days of Age.

OBJECTIVES

To establish population-based rates of invasive bacterial infection (IBI; bacteremia and/or bacterial meningitis) in febrile young infants, to compare demographic characteristics of febrile infants with IBIs with liveborn infants, to calculate performance of lumbar puncture and hospitalization proportions, and to estimate the proportion of missed IBI diagnoses.

STUDY DESIGN

We used New York State's all-payer database to identify healthy, full-term, febrile infants aged 8 to 90 days of age who were evaluated for fever in emergency departments from 2012 to 2023. Using chi square statistics, we compared IBI rates and demographic characteristics of febrile infants with IBIs with the age-stratified population. We calculated age-stratified performance of lumbar puncture, hospitalization, and missed IBI proportions.

RESULTS

Of the 2 295 788 healthy, full-term births, 66 692 infants were evaluated in emergency departments between 8 and 90 days of age with fever. The IBI rate was 5.3 of 1 000 000 infant-days and decreased significantly with advancing age to 90 days (P < .0001). Febrile infants with IBIs differed significantly by sex, type of insurance, race, ethnicity, and type of hospital emergency department (P < .00001). Lumbar puncture and hospitalization proportions decreased significantly (P < .0001) with advancing age whereas missed IBI proportions increased (P < .05). IBI rates did not change over the 12-year study period.

CONCLUSIONS

Findings demonstrate a stepwise reduction in rates of IBIs and performance of lumbar puncture and hospitalization with advancing age to 90 days, coupled with an increase in proportions of missed IBIs. Significant demographic differences exist between febrile infants with IBIs and the population of age-matched infants. Strategies to reduce IBIs and missed IBIs in high-risk groups should be pursued.