Background: Fever is a common complaint and lacking localizing signs poses a diagnostic dilemma, mostly, but not only, in children under 3 years of age. Recent years studies found common clinical markers for a Serious Bacterial Infection (SBI) to be ineffective in confirming or ruling out a suspected SBI in an environment with low prevalence of SBI such as developed countries. Shivering (chills, rigors) during a febrile illness is a common complaint in children but it's true incidence is unknown. It is assumed that shivering appears more frequently in children with SBI but only one study in the pediatric population was found to support this assumption. No studies were found to describe the frequency of shivering in the emergency department. Study purpose: To describe the frequency of febrile shivering in the pediatric population arriving at the emergency department and it's relation to a Severe Bacterial Infection. Participants: Children in the age range of 3 months to 18 years presenting with fever. Intervention: During the study time frame the frequency of febrile shivering will be documented . Patients with febrile shivering who meet the inclusion criteria, a sepsis workup will be done including blood samples for inflammatory markers, blood culture, urinalysis and urine culture when a urinary tact infection is suspected. Other systems (CSF sampling, joint fluid aspiration, stool culture, chest x ray) will be examined according to an appropriate history and clinical suspicion. The same work up will be done in next consecutive patient presenting with fever without shivering. Results: The frequency of febrile shivering, positive cultures, lobar pneumonia in a chest x ray. A comparison between the study and the control group will be made. Categorical variables will be compared using the Chi square test or Fisher exact test (as appropriate). Continuous variables will be compared using the student t test or Mann Whitney test. The relation between a bacterial infection and clinical variables will be analyzed using a logistic regression. Study group size: This is a pilot study. Investigators will use a convenience sample of all children admitted with shivering during the study period.

Safety: All examinations will be held by the emergency department organic staff in the same routine methods done otherwise outside the study settings. The emergency department and hospital protocols for patients identification and infection control will be carried out before invasive procedures. Ethics: Parents will be asked for their agreement to answer a questioner as part of the study and their agreement will be documented. Informed consent will be asked for each patient, of the legal guardian. The study will be held according to the ethics rules of the Helsinki declaration and was approved by the local Ethics board. Access to the database will be restricted to the study investigators. The database will be encrypted by a password. After gathering the data and before statistical analysis information identifying the patients will be removed. The importance of the study: Fever in children is a common complaint frequently posing a dilemma on the extent of workup needed beyond clinical evaluation. This study aims to examine the frequency of shivering among children presenting to the ED with fever , its ability to predict the risk of severe bacterial infection.