In the summer of 2020, much of the world was preparing to reopen schools, which most places had closed in spring 2020. The science was showing that children weren’t particularly vulnerable to the novel coronavirus, and the data from many countries showed that in-person schooling didn’t increase the spread of the virus.

The U.S., in general, appeared likely to follow the rest of the world.

But then-President Donald Trump made the mistake of saying a good, true, and important thing: that schools should open.

The political class on the Left reacted by locking down harder. Joe Biden’s Democratic National Committee put out an attack ad against Trump. Yes, that's right, Biden campaigned for president on keeping schools closed .

States, cities, and counties followed Biden instead of the science and barred the schoolhouse doors — many of them for a year or more.

The last three years have shown us a parade of evidence about the wretched outcomes of this experiment — what one celebrated health czar called the “ downstream effects .” These include learning loss, anxiety, depression, violence, and drug abuse.

A new study from the British Medical Journal’s Evidence-Based Medicine looks at hundreds of countries that tried different approaches. It finds that not only did school closures inflict all sorts of harm on the children locked out of school, but they also did not slow the spread of COVID.

The study found massive learning loss in the countries that closed schools for longer compared to countries that reopened sooner. Sweden, for instance, experienced no learning loss at all and saw no widening of educational gaps. The U.S., obviously, saw massive learning loss and significant widening of educational achievement gaps along racial and socioeconomic lines.

Here is the authors’ summary of findings on the other downstream effects:

Point out these harms from closing schools, and you will inevitably get angry folks accusing you of wanting to kill children or grandma. But this same study finds that school closures provided only “limited benefits on COVID-19 transmission.” Teachers in wide-open Sweden, for instance, were no more likely than teachers in other countries to be hospitalized with COVID.

You can take issue with this study if you want, but as of now, the science overwhelmingly shows that extended school closures were a massive mistake. They harmed children and did not meaningfully slow the spread of the coronavirus.