We are closing schools to limit the spread of COVID-19 and, at the same time, telling older people, who are most vulnerable to the virus, to avoid children, who are less likely to fall ill but very likely to be carriers. We have not yet reckoned with the collision of these two public health efforts.

In a 2018 survey of American grandparents by AARP, 38% said they considered themselves caregivers or baby sitters to their grandchildren, including 11% who lived in the same household as their grandchildren. A 2014 Pew survey found that 22% of grandparents provided regular child care for a grandchild. How are we going to square this circle of child care when we separate the elders from the kids?

Consider just three questions that arise when grandparents are removed from the family picture. First, where schools are still open and parents can go to work but elders have been sidelined, who is going to do what millions of grandparents do every day: Take care of kids after school, before parents are home from work? Second, where schools are closed but parents are still expected to go to work or cannot afford to stay at home, who is going to take on the all-day child care? Third, where schools are closed and parents are lucky enough to have jobs they can do remotely, who is going to keep those kids entertained at home while their parents are at their computers?

Plenty of parents reading this are saying: "Wish I had that problem. Wish I had parents willing or able to help with child care." I am familiar with those parents. Run into them all the time at the park, at community events, at the pickup circle at school. Over and over, I hear how lucky my daughter and son-in-law are to have loving, reliable, active, healthy and, yes, unpaid adults on deck for after-school care. So true. But my husband and I are not unique. My next-door neighbor tends to some subset of her 13 grandchildren at their homes or hers every single day of the workweek, and her frail 93-year-old mother now lives with her. Last spring, when talking about grandchild care with a nurse in my physician's office, she said, "I don't know what I'd do without my father to take care of the kids." Millions of Americans are like my neighbor's adult kids and that nurse. Their work schedules and family economies are based on grandparent care, and they have no Plan B in this public health crisis.

In my neighborhood, the local high school babysitter gets $15 an hour for managing three kids. Even if she's willing to step in now that Pennsylvania's schools are closed, my daughter will spend $2,400 in child care in one month. That's the child-care cost that is impoverishing working parents who have preschool children but lack child care help from grandparents. What will such costs do to families with school-age children who have not budgeted for this? What will it do to their ability to buy anything else in this economy already spiraling downward?

Washington state's governor, Jay Inslee, was right when he told a reporter last week that the "penalty" for holding big family events is simple: "You might be killing your granddad." It was a stark message that put the focus right where it should be, on protecting one another, especially the most vulnerable. But that viral reality does not mean grandparents have suddenly become passive, helpless objects. Vulnerable though we be, grandparents are also important agents in millions of families. The granddad you kill may be the one who picks up the kids at school every day.

A full grasp on our current situation demands that we make the link between paid work, school and the unpaid work of grandparents who provide child care in every ZIP code. Without a decent, affordable child-care system, flexible work hours and paid sick leave, the over-65 population is propping up families all over the U.S. by performing essential child care for free. Remove those grandparents from the family system, and we get yet another breakdown in our social system. Don't remove them, and you may kill Granddad — or Grandma. Paradoxically, we constitute the labor force that parents most need right now. How do families decide what to do?

Last week, recalling the many days I spent in the hospital with pneumonia-laced flu two years ago, our grandkids' parents decided to lay us off from our child-care jobs. When I pushed back, my son-in-law gave me a wonderfully loving and wholly pragmatic answer: "We cannot afford to have anything happen to you, Nana." So true.

But what happens to me if I cannot see my grandchildren for — how long? Anyone have a cure for the hole that bores into my heart?

Victoria Bissell Brown is retired from the faculty of Grinnell College in Iowa, where she taught United States history. She is writing a history of American grandmothers since 1945. She wrote this article for the Washington Post.