The dramatic surge of excess mortality in the United States between 2017 and 2021

A mortality gap between the United States and other high-income nations emerged before the pandemic. International comparisons of Covid-19 mortality suggest this gap might have increased during the pandemic. Applying average mortality rates of the five largest West European countries to the US population shows that the number of "excess deaths" attributable to this mortality gap continues to increase year after year in the United States. The annual number of such excess deaths has doubled between 2017 and 2021, with most of the increase occurring during the pandemic (+89.1% between 2019 and 2021). In 2021, excess mortality in the United States relative to its European peers contributed 892,491 excess deaths, amounting to 25.8% of all US deaths that year, up from 15.7% in 2017. Of the 450,224 excess deaths added between 2017 and 2021, 42,317 are attributable to population change (9.4%), 230,672 to differential rates of Covid-19 mortality (51.2%), and the remaining 177,235 to differential rates of mortality from other causes (39.4%, possibly including misclassified deaths due to Covid-19). The contribution of Covid-19 mortality to excess mortality in the United States (relative to its European peers) grew between 2020 and 2021 due to diverging trends in Covid-19 mortality, especially towards the end of 2021 as US vaccination rates plateaued at lower levels than in European countries. While this contribution might be transient, divergent trends in mortality from other causes persistently separates the United States from West European countries. Excess mortality is particularly high between ages 15 and 64. In 2021, nearly half of all US deaths in this age range are excess deaths (48.0%).