Objectives
Circulating nucleocapsid (NCP) antigen of SARS-CoV-2 is increased in severely ill COVID-19 patients. However, clinical deterioration of COVID-19 often happens about one week after benign initial presentation. The role of NCP antigenemia as a biomarker in those cases remains unclear. We investigated NCP clearance kinetics in hospitalized patients as a risk assessment tool for predicting necessity of intensive care treatment of COVID-19 patients.