U.K. “challenge” trials will infect healthy volunteers with COVID-19

Read MoreAs the world surpasses 40 million confirmed coronavirus cases, there is now a call for volunteers in the U.K. willing to be infected with the virus in the first-ever COVID-19 “challenge” trial. Elizabeth Palmer reports.As the world surpasses 40 million confirmed coronavirus cases, there is now a call for volunteers in the U.K. willing to be infected with the virus in the first-ever COVID-19 “challenge” trial. Elizabeth Palmer reports.