Three weeks ago on these pages, my colleague V.V. Chari and I asserted that a limited mass quarantine period would make sense only if we used the time it bought us to radically change the facts on the ground regarding our ability to test and trace.

Thankfully, it appears our state has indeed used this time to increase its ability to test, trace and isolate.

But we also warned that at the end of any time-limited mass quarantine, we would still be almost where we started — with a small fraction of the population infected and able to infect almost everybody else — and thus facing extension of our mass quarantine.

What are the benefits of continuing our lockdown (albeit as slightly relaxed last week)? I see three.

One benefit is we are buying time to develop an effective vaccine or treatment. But should we be confident such a reprieve is coming any time soon? The number of times humankind has created an effective vaccine against any coronavirus currently stands at zero. While some antiviral treatments have shown promise, hopes that a "magic bullet" treatment is soon forthcoming are exactly that — hopes.

A second benefit is that "flattening the curve" through a prolonged shutdown can change the fraction of us who will eventually get this disease even without a vaccine. But this effect is smaller than one might guess.

Absent a vaccine, the epidemiology models governments currently use predict that unless we take extreme mitigation measures forever, at least 60 to 70% of us will eventually get this disease. Long-term shutdowns can change how high a fraction above this 60 to 70% eventually get infected, but not the fact that the majority of us will get infected.

A third benefit of a prolonged shutdown is that it is certainly better to get COVID-19 (or cancer, or a heart attack, or a stroke) when the hospital system is not overwhelmed. Yet in part due to many truly heroic efforts of our medical community, our system has not been overwhelmed, and other than in New York City, has not been close to being overwhelmed.

Temporary facilities are being dismantled, never used. While this does not answer whether hospitals would have been overwhelmed but for the extreme mitigation measures taken, it does imply (with the benefit of hindsight) that less-restrictive measures would have been sufficient, especially outside of New York.

So far, hospitals have not been overwhelmed in Sweden or anywhere measures less restrictive than ours have been taken.

Are these benefits of a continued shutdown sufficient to justify the horrific costs it imposes, especially on the young? I believe not, and instead see continuing our current policies for much longer as generational theft.

Preschool children are losing irreplaceable schooling shown to be crucial in cognitive development. K-12 students are losing schooling shown to have huge returns to their future earning abilities. Undergraduate, graduate and professional students are delaying their productive careers.

The currently unemployed are disproportionally young and losing not only paychecks, but extremely valuable on-the-job experience. Further trillions are being added to the national debt, to be paid by future taxpayers, the young.

All for a disease that has, while not exactly zero, a very low chance of killing anyone under 40. (In Chicago, out of more than 600 deaths so far, exactly three of the deceased were under 30, with another 13 between 30 and 40).

We are sacrificing the futures of our young to protect the old, and mostly the very old.

Some of the catastrophic economic costs our young are paying are due to the epidemic itself, but many are due to the shutdown policies. I believe we need to substantially relax restrictions, now or soon. We cannot wait months or years for a vaccine or treatment that may never come.

Other countries have shown we can protect against overwhelming our hospitals without shutting down the economy. We can allow individuals and businesses to make their own decisions on balancing risks. While not perfect, such private voluntary actions will slow infection rates. Policies of aggressive testing, tracing and isolating slow infection rates as well.

At-risk individuals (including the elderly) who are able to make it through the day without help eating, getting dressed and showered can make their own decisions regarding how much to expose themselves, and where necessary we should make it financially feasible for them to limit their exposure. For those who do need daily help, we need to do the best we can to protect them.

But this cannot come at the cost of ruining the futures of their grandchildren and great-grandchildren.

Christopher Phelan is professor and chair, University of Minnesota Department of Economics.