The first case of COVID-19 infection was identified in Bergen on 28th February in Bergen prior to the declaration of pandemic on 11th March 2020. Our interdisciplinary consortium covering the community Bergen Legevakt, hospitals (HUS, HDS and SUS) and University of Bergen aims to understand key clinical, epidemiological, and immunological characteristics of COVID-19 infection in the general population, hospitalised patients and frontline healthcare workers (HCW). We commenced our study on 6th March collecting baseline pre-exposure and demographics data and serum samples from 613 HCW. These HCW will be followed up upon suspected or confirmed infection or after 2 months to collect exposure history and serum samples. Serological assays have been established in which only infected people have antibodies and allowing us to map exposure. Exposure history and clinical symptoms and blood samples will be collected from all COVID-19 positive community cases and their household/close contacts. We will define levels of population based immunity to SARS-CoV-2 virus in HCW (exposed and/or infected), community and hospitalized patients and the durability of immunity. We will describe the prognostic factors for severe and life-threatening illness in hospitalized patients (n=49 already recruited) and investigate immunological biomarkers for severe disease.