RADx Variant Task Force Program for Assessing the Impact of Variants on SARS-CoV-2 Molecular and Antigen Tests

<italic>Goal:</italic> Monitoring the genetic diversity and emerging mutations of SARS-CoV-2 is crucial for understanding the evolution of the virus and assuring the performance of diagnostic tests, vaccines, and therapies against COVID-19. SARS-CoV-2 is still adapting to humans and, as illustrated by B.1.1.7 (Alpha) and B.1.617.2 (Delta), lineage dynamics are fluid, and strain prevalence may change radically in a matter of months. The National Institutes of Health&#x0027;s Rapid Acceleration of Diagnostics (RADx^SM) initiative created a Variant Task Force to assess the impact of emerging SARS-CoV-2 variants on <italic>in vitro</italic> diagnostic testing. Working in tandem with clinical laboratories, the FDA, and the CDC, the Variant Task Force uses both <italic>in silico</italic> modeling and <italic>in vitro</italic> testing to determine the effect of SARS-CoV-2 mutations on diagnostic molecular and antigen tests. Here, we offer an overview of the approach and activities of the RADx Variant Task Force to ensure test performance against emerging SARS-CoV-2 lineages.