Americans seem resigned to the idea that life won't return to normal until we have an approved and widely-distributed vaccine for COVID-19, but vaccine optimism could be undermining other efforts to control the spread of the virus. Dan is joined by Tom Frieden, who led the Centers for Disease Control from 2009 to 2017, to discuss how realistic it is to hope for a vaccine by year-end — and what will still need to happen even when we have it.