Last spring and summer, we read many articles about Europe’s success in keeping its schools open, based on the belief that young children are less likely to get sick with COVID-19 and less likely to spread it.

Ruth Bender reports in The Wall Street Journal that European nations are closing their schools because new studies show that children do get the disease and are likely to spread it.

As U.S. authorities debate whether to keep schools open, a consensus is emerging in Europe that children are a considerable factor in the spread of Covid-19—and more countries are shutting schools for the first time since the spring.

Closures have been announced recently in the U.K., Germany, Ireland, Austria, Denmark and the Netherlands on concerns about a more infectious variant of the virus first detected in the U.K. and rising case counts despite lockdowns.

While the debate continues, recent studies and outbreaks show that schoolchildren, even younger ones, can play a significant role in spreading infections.

“In the sec­ond wave we ac­quired much more ev­i­dence that school­children are al­most equally, if not more in­fected by SARS-CoV-2 than oth­ers,“ said An­toine Fla­hault, di­rec­tor of the Uni­ver­sity of Gene­va’s In­sti­tute of Global Health.

Schools have rep­re­sented one of the most con­tentious is­sues of the pan­demic given the pos­si­ble long-term im­pact of clo­sures on chil­dren and the eco­nomic fall­out from par­ents be­ing forced to stay home.

The re­cent shut­down of schools was es­pe­cially dra­matic in Eng­land. U.K. Prime Min­is­ter Boris John­son ini­tially planned to keep el­e­men­tary schools there open af­ter the Christ­mas break, but changed course amid soar­ing in­fec­tions. Af­ter one day back, schools were closed un­til fur­ther no­tice. Plans to grad­u­ally re­open high schools through Jan­uary were also scrapped.

“The prob­lem is not that schools are un­safe for chil­dren,” Mr. John­son said last week. “The prob­lem is schools may none­theless act as vec­tors for trans­mis­sion, caus­ing the virus to spread be­tween house­holds.”

As re­cently as No­vember, Eu­ropean pol­icy mak­ers were adamant that schools would gen­er­ally re­main open through the cur­rent wave of in­fec­tions, with short-term clo­sures lim­ited to sin­gle schools or classes when­ever new cases were iden­ti­fied.

Many school districts have remained open or tried to open during the battle over whether opening was safe.

Yet sci­en­tists in Eu­rope say that the lat­est re­search sug­gests oth­er­wise. Mr. Fla­hault said an an­ti­body sur­vey con­ducted by re­searchers in Geneva in May and De­cem­ber, us­ing thou­sands of ran­dom sam­ples, found that chil­dren of age 6 to 18 were get­ting in­fected as of­ten as young adults. The study has yet to be peer re­viewed….

In Aus­tria, a na­tion­wide sur­vey by uni­ver­si­ties and med­ical in­sti­tutes found that chil­dren un­der 10 showed a sim­i­lar rate of in­fec­tion to those be­tween 11 and 14, and that the chil­dren in gen­eral were get­ting in­fected as of­ten as teach­ers, said Michael Wag­ner, a mi­cro­bi­ol­o­gist at the Uni­ver­sity of Vi­enna who over­sees the study.