Validation of a Proteomic Signature and Assessment of Viremia in Children With Fever Without Source

The study is an observational blinded Validation study in pediatric patients below 3 years old with a diagnosis of Fever Without Source (FWS). In this study the investigators aim to validate the performance of a proteomic signature aiding the physicians to discriminate between viral and bacterial infections in febrile children. The study will also assess the prevalence of Human Enteroviruses (HEV), Human Parechoviruses (HPeV), Adenovirus (AdV) and Human Herpesvirus type 6 (HHV-6) viremia, as well as Kingella Kingae bacteremia in the study cohort.