Why does Covid-19 make some people so much sicker than others? Risk factors and pre-existing conditions are part of it, but could there still be another factor? CNN Chief Medical Correspondent Dr. Sanjay Gupta talks to infectious disease expert Dr. Monica Gandhi about the possible role of viral dose in this pandemic.To learn more about how CNN protects listener privacy, visit <a href="https://cnn.com/privacy">cnn.com/privacy</a> Learn more about your ad choices. Visit <a href="https://podcastchoices.com/adchoices">podcastchoices.com/adchoices</a>

A Surge in South Dakota

All over the world, there are people who are living extraordinary lives, full of happiness and health – and with hardly any heart disease, cancer or diabetes. Dr. Sanjay Gupta has been on a decades-long mission to understand how they do it, and how we can all learn from them. Scientists now believe we can even reverse the symptoms of Alzheimer’s dementia, and in fact grow sharper and more resilient as we age. Sanjay is a dad – of three teenage daughters, he is a doctor - who operates on the brain, and he is a reporter with more than two decades of experience - who travels the earth to uncover and bring you the secrets of the happiest and healthiest people on the planet – so that you too, can Chase Life.