What we know about the risk of asymptomatic spread of coronavirus
The World Health Organization is walking back a comment suggesting that the spread of COVID-19 from an asymptomatic person is rare. Dr. Ashish K. Jha, director of the Harvard Global Health Institute, joins CBSN to discuss when patients are the most contagious, and a new Harvard Medical School study which suggests the coronavirus may have been in China as early as August.