Following the development, validation and establishment of the MULTICOV-AB assay within the CORESMA project, the Multiplex Immunoassays group has now received additional funding to enable its use in several projects. MULTICOV-AB, a multiplex immunoassay, allows parallel testing of individual immune responses against different proteins or protein fragments of the novel SARS-CoV-2 virus and the common endemic coronaviruses NL63, OC43, 229E, and HKU1. In this project, MULTICOV-AB will be used to screen infection/vaccination status in vulnerable populations (e.g., clinicians, immunocompromised individuals), as part of seroprevalence studies to assess the spread of SARS-CoV-2 in the population, and to assess humoral responses following vaccination.