After-school activities are creating clusters where coronavirus can spread among children, said Dr. Rochelle Walensky, director of the US Centers for Disease Control and Prevention. The virus was linked to high school wrestling tournaments in Florida last December where 38 people tested positive, according to a CDC report published in January. In Minnesota, the B.1.1.7 variant of SARS-CoV-2 spread through Carver County with at least 68 cases linked to youth sport activities including hockey, wrestling and basketball, according to the Minnesota Department of Health.