Social distancing — canceling large gatherings, closing schools and offices, quarantining individuals and even sequestering entire cities or neighborhoods — seems to be the best way to slow the spread of the coronavirus. But it’s a crude and costly public health strategy. Shuttering shared spaces and institutions means families lose child care, wages and social support. What’s more, it’s insufficient to protect the older, sick, homeless and isolated people who are most vulnerable to the virus. They need extra care and attention to survive, not society’s back.

I learned this firsthand while studying another recent health crisis, the great Chicago heat wave of 1995. In that event, as in so many other American disasters, social isolation was a leading risk factor and social connections made the difference between life and death.

In Chicago, social isolation among older people in poor, segregated and abandoned neighborhoods made the heat wave far more lethal than it should have been. Some 739 people died during one deadly week in July, even though saving them required little more than a cold bath or exposure to air-conditioning. There was plenty of water and artificial cooling available in the city that week. For the truly disadvantaged, however, social contact was in short supply.

Good governments can mitigate damage during health crises by communicating clearly and honestly with the public and providing extra service and support to those in need. But as the heat settled into Chicago, the mayor focused more on public relations than public health. He neglected to issue an official emergency or call in additional paramedics until it was too late. He publicly challenged the medical examiner’s reports that hundreds were dying from heat. In news conferences, he insisted that his administration was doing everything possible. His health service commissioner blamed those who died for neglecting to take care of themselves.