Earlier this week the CDC changed its mask guidance, advising that those who are fully vaccinated can go mask free in most circumstances. It's a major milestone in the pandemic fight, but after a year when we’ve faced one deadly surge after another, what makes federal health authorities so sure loosening the rules will be safe? On this edition of KCBS In Depth, we consider the positive vaccine data that's reassuring medical experts. 

Guests: 

• Dr. Monica Gandhi, infectious disease physician and professor of medicine, UC San Francisco 
• Dr. Michele Barry, professor, Stanford University’s School of Medicine | director, Center for Innovation in Global Health

Host: Keith Menconi