Even in 2020, Sweden’s worst year of the pandemic, the mortality rate remained normal among Swedes under 70. Meanwhile, the death rate surged among younger adults in the U.S., and a majority of them died from causes other than Covid. In Sweden, there have been no excess deaths from non-Covid causes during the pandemic, but in the U.S. there have been more than 170,000 of these excess deaths.

No one knows exactly how many of those deaths were caused by lockdowns, but the social disruptions, isolation, inactivity and economic havoc clearly exacted a toll. Medical treatments and screenings were delayed, and there were sharp increases in the rates of depression, anxiety, obesity, diabetes, fatal strokes and heart disease, and fatal abuse of alcohol and drugs.

These were the sorts of calamities foreseen long before 2020 by eminent epidemiologists such as Donald Henderson, who directed the successful international effort to eradicate smallpox. In 2006 he and colleagues at the University of Pittsburgh considered an array of proposed measures to deal with a virus as deadly as the 1918 Spanish flu.

Should schools be closed? Should everyone wear face masks in public places? Should those exposed to an infection be required to quarantine at home? Should public-health officials rely on computer models of viral spread to impose strict limitations on people’s movements? In each case, the answer was no, because there was no evidence these measures would make a significant difference.