Mucosal Immunity Against SARS-CoV-2 Infection in COVID-19 Patients

Objective: Primary Objective: to analyse the development of mucosal immunity against SARS-CoV-2 in nasal fluid of Covid-19 patients and their household contacts Secondary Objective(s): * To descriptively analyse the correlation of mucosal antibodies with viral diagnostics and disease symptoms * To determine the correlation between mucosal and serum antibody levels * To study the functionality of serum and mucosal antibodies Study design: A single-site, observational, prospective cohort study among COVID-19 patients and their household contacts Study population: The study will be conducted among COVID-19 patients with a laboratory-confirmed infection with SARS-CoV-2, as well as household contacts remaining in home quarantine at the same address, among secondary and tertiary hospital careworkers in the provinces of Gelderland and Noord-Brabant in The Netherlands. Intervention (if applicable): N/A Main study parameters/endpoints: Mucosal antibodies: descriptive analysis of SARS-CoV-2 IgG, IgA, IgM and IgD concentrations in nasal fluid at the various collection moments. Viral diagnostics: presence of SARS-CoV-2 in diagnostic specimens collected at inclusion visit. Disease symptoms: presence of respiratory complaints in participants. Serum antibodies: descriptive analysis of SARS-CoV-antibody concentrations in serum at day 28 Antibody functionality: descriptive analysis of antibody functionality of serum and nasal fluid samples, including virus neutralization