Demographers find that
a hypothetical 1 million US deaths in the COVID-19 epidemic would mean a drop in life expectancy for 2020 by 2.9 years, equivalent of U.S. mortality levels in 1995.

The scenario of 1 million COVID-19 deaths is similar in scale to that of the decades-long HIV/AIDS and opioid-overdose epidemics but considerably smaller than that of the Spanish flu of 1918.

See https://news.berkeley.edu/2020/08/25/demographers-put-covid-19-death-toll-into-perspective/