Background:~Infections in young infants is a challenge as 1) it is often not possible to distinguish serious bacterial infection (SBI) from viral infection by clinical appearance alone, 2) a causative organism is often not identified and 3) due to relatively low sensitivity and specificity of current biomarkers. The consequence is overtreatment with antibiotics being prescribed to as many as 50% of febrile young infants presenting to emergency departments. However, the majority of these children does not have a bacterial infection. Host RNA expression profiling has shown high sensitivity and specificity for discriminating bacterial from non-bacterial infections in preliminary studies of febrile young infants.~Methods:~A prospective multicentre observational study including young infants admitted and evaluated due to suspected infection at the 4 paediatric acute care units in the Capital Region of Denmark (Rigshospitalet, Hvidovre Hospital, Herlev Hospital, Nordsjællands Hospital - Hillerød). Whole blood will be collected in PAXgene blood RNA tubes and analysed by RNA sequencing at the Centre for Genomic Medicine, Rigshospitalet. Host RNA expression profiles will be identified in a discovery cohort and the diagnostic performance will be tested in a validation cohort. A control group of healthy and afebrile young infants will be included.~Time frames:~Patient recruiting: May 15th 2020 to February 28th 2022. Sample analysis (RNA sequencing): March 1st 2022 to August 31st 2022.~Perspectives:~New molecular-based diagnostic tools complementary to conventional methods may optimise infection management in young infants by improving early diagnostics and allowing early modification of antibiotic treatment. This will reduce antibiotic resistance, side effects, unnecessary hospitalisation and invasive procedures.
This study seeks to identify and test host RNA expression profiles as markers for infections in young infants. Preliminary studies have shown high sensitivity and specificity for the discrimination of bacterial from non-bacterial infections in children, but the method has only been investigated in a limited number of young infants. The study aims to include 65 young infants with serious bacterial infections. The samples will be analysed by RNA sequencing. New diagnostic tools may help reduce unnecessary antibiotic treatment, antibiotic resistance, side-effects, hospitalisation and invasive procedures.