On Mar. 29, 2023, the mortality gap between the United States and other high-income nations substantially expanded during the first two decades of the 21st century according to a study published in PLOS ONE. International comparisons of Covid-19 mortality suggest this gap might have grown during the Covid-19 pandemic.

In 2021, the number of excess deaths involving Covid-19 in the United States reached 223,266 deaths, representing 25.0% of all excess deaths that year.