CNN chief medical correspondent Sanjay Gupta, MD, offers an accessible, data-packed answer to our biggest questions about Covid-19: What have we learned about this pandemic and how can we prepare for--or prevent--the next one? As America's favorite frontline Covid-19 health journalist, Dr. Sanjay Gupta has barely left his primetime seat in his makeshift studio basement since the pandemic began (other than to perform brain surgery). He's...