It's been a year since the first case of COVID-19 was diagnosed in the U.S. Since then the U.S. has seen more than 25 million cases of COVID-19 and more than 400,00 deaths. This has taken a significant emotional toll on the nation.

COVID-19 is a disease that affects the entire health care system, and emergency medical teams are often on the front lines receiving infected patients. The challenges have been numerous as symptoms varied, screening protocols changed, and lifesaving treatments have been developed.

In this Mayo Clinic Q&A podcast: Dr. Annie Sadosty, a Mayo Clinic emergency medicine physician, reflects on this past year and the ever-changing battle against COVID-19.