The disease was the third leading cause of death for much of 2020, but became the leading cause of death in December 2020 and early 2021, reaching a peak of 3,136 deaths per day in January 2021 and far surpassing U.S. deaths from heart disease and cancer during that time. Heart disease is typically the number one cause of death (about 2,000 a day), while cancer claims about 1,600 lives a day, according to the Peterson-KFF Health System Tracker.