WHEN AMERICAN hospitals first began treating covid-19 patients early last year, health-care workers did not have an official way to categorise them. Initially they were advised to classify such patients by some of the symptoms they were suffering from, such as “viral pneumonia” or “acute respiratory distress syndrome”. It was only on April 1st, after the outbreak became an epidemic, that the Centres for Disease Control and Prevention (CDC) adopted the emergency diagnosis code created to document patients with “SARS-CoV-2”. Data released on March 31st show that, over the next nine months, that code was listed as the underlying cause of 345,323 deaths in America, making covid-19 the third-leading cause of death in 2020 (see chart).

Even this figure undercounts the pandemic’s true death toll. According to provisional estimates from the CDC, mortality from all causes increased by 17.7% in 2020 from 2,854,838 to 3,358,814, a difference of more than 500,000. (Deaths typically grow by 1-2% a year because of population growth and aging.) Although most of this increase was caused by covid-19, more than 30% of these “excess deaths” were attributed to other illnesses. Figures compiled by Farida Ahmad and Robert Anderson of the CDC’s National Centre for Health Statistics suggest that deaths from heart disease increased by 4.8% in 2020. Deaths also increased markedly for influenza and pneumonia (7.5%), Alzheimer’s disease (9.8%), unintentional injury (11.1%) and diabetes (15.4%).

At least some of these people probably had undiagnosed cases of covid-19. Those with diabetes and heart disease, for example, are particularly vulnerable to severe cases of covid-19. Others may have died prematurely after not seeking treatment for a chronic illness or facing disruptions to their normal care. Such disruptions appear to have had a bigger impact on some than on others. A paper published on April 2nd by a team of researchers led by Steven Woolf of Virginia Commonwealth University estimates that, between March 1st 2020 and January 2nd 2021, African-Americans accounted for more than a sixth of excess deaths in America, despite comprising only an eighth of the population.