Emergency PWAS in Respiratory Infectious Disease

Inclusion Criteria: Patients eligible for enrolment include: With reference to previous inclusion criteria are: * Adults ≥18 years of age; AND * Suspected, acute, community-acquired, respiratory, infectious disease (scaRID)\*; AND * Informed consent. Note: scaRID is defined according to ALL three criteria: 1. Community acquired (not hospitalised for \<28 days); AND 2. Acute infection (defined as symptom onset \<8 days and any ONE of reported fever or chills or aural temperature \>37.5°C or hypothermia or leucocytosis or leucopaenia or new altered mental status); AND 3. Probable respiratory infection - According to any ONE of: 1. new cough or new sputum production or 2. chest pain or 3. dyspnoea or 4. tachypnoea or 5. abnormal lung examination or 6. respiratory failure; or 7. physician's judgment (presenting with systemic or gastrointestinal symptoms). Control subjects will be drawn from two groups: * The worried well - adult patients with a National Early Warning Score (NEWS) \<3 and a temperature \<37.5°C. * Relatives or accompanying friends with no acute illness. Exclusion Criteria: * Refusal of consent; * Recent hospitalisation (\<28 days); * Enrolled in another clinical trial * Cellulitis; * Skin or orthopaedic infections; * Urinary tract infection; * Acute abdominal sepsis; * Sexual transmitted disease; * Human immunodeficiency virus (HIV) infection; * Immunocompromised/potential neutropenic fever; * Solid organ or haematopoietic stem-cell transplant within the previous 90 days; * Active graft-versus-host disease or bronchiolitis obliterans; * Severe traveller's disease requiring urgent hospitalisation and management including malaria, dengue, typhoid and other rickettsial diseases; * Stroke; * Toxidrome; * Non-organic acute psychosis.