Evaluating a Host-response Based Diagnostic for Distinguishing Between Bacterial and Viral Etiology in Patients With Lower Respiratory Tract Infection (LRTI)

Inclusion criteria

• Patients aged 18 years and older who agree (or their legal guardian agree) to sign an informed consent will be eligible for inclusion.
• The LRTI cohorts should also fulfill the following criteria:

• Peak measured (not tactile, self-reported acceptable) temperature ≥ 37.8°C (100°F) within the last 7 days (AND)
• Symptoms duration ≤7 days (AND)
• Clinical suspicion of LRTI or pneumonia

Exclusion criteria

• Oral/intravenous/intramuscular antibiotic treatment of over 48/12/12 hours' duration at time of enrollment (respectively), unless temperature ≥ 37.8°C was measured within the last 2 days
• Another episode of an acute infection during the last 2 weeks
• Congenital immune deficiency (CID)
• A proven or suspected human immunodeficiency virus (HIV)-1, hepatitis B virus (HBV), or hepatitis C virus (HCV) infection
• Active malignancy
• Pregnancy
• Current treatment with immune-suppressive or immune-modulating therapies including without limitations:

• Use of high dose steroids >1 mg/kg/day prednisone or equivalent in the past two weeks
• Monoclonal antibodies
• Intravenous immunoglobulin (IVIG)
• Cyclosporine, Cyclophosphamide, Tacrolimus
• Granulocyte/Monocyte colony stimulating factor (G/GM-CSF)
• Anti-Tumor Necrosis Factor (TNF) agents
• Interferon (of all kinds)
• Other severe illnesses that affect life expectancy and quality of life such as:

• Moderate to severe psychomotor retardation
• Post-transplant patients (including solid organs, allogeneic/autologous stem cell transplantation)
• Moderate to severe congenital metabolic disorder