Rate of invasive bacterial infection in recently vaccinated young infants with fever without source

Abstract

ObjectiveTo compare the rates of invasive bacterial infection (IBI) (bacterial pathogen in blood or cerebrospinal fluid) and urinary tract infection (UTI) in febrile infants between 42 and 90 days of age who had and had not been vaccinated in the previous 48 hours.DesignObservational study; secondary analysis of a prospective registry-based cohort study.SettingPaediatric emergency department.PatientsInfants 42–90 days of age with fever without source seen between 2010 and 2021.Main outcome measuresRates of IBI (bacterial pathogen in blood or cerebrospinal fluid) and UTI (urine culture obtained by an aseptic method yielding growth of ≥10 000 cfu/mL with associated leucocyturia).ResultsWe included 1522 infants, including 185 (12.2%) vaccinated in the previous 48 hours. Overall, 19 (1.25%) were diagnosed with an IBI and 282 (18.5%) with a UTI. No recently immunised infants were diagnosed with an IBI (vs 19, 1.4% of those not recently immunised, p=0.2). The UTI rate was higher in infants not recently immunised (20.1% vs 7.0%, p<0.01; OR: 3.3 (1.9–5.9)).ConclusionsAlthough the rate of UTI in recently immunised infants 42–90 days old with fever without a source is lower than in those not recently immunised, recommending screening for UTI seems appropriate. If the lower rate of IBI among recently immunised well-appearing infants is confirmed, the recommendation to systematically perform blood tests in these infants should be reconsidered.

Conundrums in the Management of Febrile Infants under Three Months of Age and Future Research

“…It is useful to note that other vaccine-induced fevers also yield similar results. A more recent study conducted after the introduction of meningococcal B included 185 patients who presented with fever post vaccination [45]. Of these, 83.3% (n = 155) received the hexavalent vaccine, which included meningococcal B. UTI was the only SBI found in this recently vaccinated cohort, and there were no cases of IBI [45].…”

Prevalence of invasive bacterial infection in febrile infants ≤90 days with a COVID-19 positive test: a systematic review and meta-analysis

“…The included studies were observational and case reports. Three were prospective, one was a prospective registry of febrile infants from one hospital with several publications [45][46][47] and the rest were retrospective. Two other reports were unpublished data presented in Pediatric Emergency Medicine meetings.…”