Centro Hospitalar Universitário de São João; Instituto de Investigação e Inovação em Saúde; Administração Regional de Saúde do Norte.
The longitudinal study will follow individuals with high-risk exposure to the virus and patients with COVID-19 (mild and severe), over approximately three months, to determine the period of contagion of the virus, its replication and viability and to identify its clinical and immunological determinants.