Just how did the Covid-19 pandemic spread to humans? It’s a question that for many already seemed to have an answer, but in recent weeks a growing number of scientists -- and now even the president -- are calling for a second look.

On this edition of KCBS In Depth, we reexamine the competing theories about the origin of the virus that causes Covid-19.

Guests: 

• Dr. David Relman, professor of medicine and of microbiology and immunology, Stanford University
• Josh Rogin, foreign policy columnist, Washington Post | author, “Chaos Under Heaven: Trump, Xi and the Battle for the 21st Century” 

Host: Keith Menconi