Antigen Detection Tests
Tests that detect respiratory syncytial virus or influenza virus antigens by immunoassay directly from clinical specimens have been commercially available for decades, are of low complexity, and may provide results within minutes at the point of care (40). Current tools for influenza and respiratory syncytial virus suffer from suboptimal sensitivity to rule out disease (41, 42); the same challenge would probably exist for SARS–CoV-2, and tests would need to be implemented with clear guidance on correct interpretation. Prototypes of such tests for other novel coronaviruses have not received regulatory approval (43, 44) but are under development (45). Monoclonal antibodies against the nucleocapsid protein of SARS–CoV-2 have been generated, which might form the basis of a future rapid antigen detection test (20).