Coronavirus variants are fueling an alarming surge in Europe,

More transmissible U.K. version likely driving uptick.

The virus swept MILAN — through a nursery school and an adjacent elementary school in the Milan suburb of Bollate with amazing speed. In a matter of just days, 45 children and 14 staff members had tested positive.

Genetic analysis confirmed what officials already suspected: The highly contagious coronavirus variant first identified in England was racing through the community, a densely packed city of nearly 40,000 a 15-minute drive from Milan.

“This demonstrates that the virus has a sort of intelligence . ... We can put up all the barriers in the world and imagine that they work, but in the end, it adapts and penetrates them,” lamented Bollate Mayor Francesco Vassallo.

Bollate was the first city in the Lombardy region to be sealed off from neighbors because of virus variants that the World Health Organization says are powering another uptick in infections across Europe. The variants also include versions first identified in South Africa and Brazil.

What’s happening

Europe recorded 1 million new COVID-19 cases last week, an increase of 9% from the previous week and a reversal that ended a sixweek decline in new infections, WHO officials said.

“The spread of the variants is driving the increase, but not only,” said Dr. Hans Kluge, WHO regional director for Europe, citing “also the opening of society, when it is not done in a safe and a controlled manner.”

The variant first found in the U.K. is spreading significantly in 27 European countries monitored by WHO and is dominant in at least 10 countries: Britain, Denmark, Italy, Ireland, Germany, France, the Netherlands, Israel, Spain and Portugal.

Why it matters

The U.K. variant is up to 50% more transmissible than the novel coronavirus that surged last spring and again in the fall, making it more adept at thwarting measures that were previously effective. Scientists say it is also more deadly.

New restrictions

In Lombardy, intensive care wards are again filling up, with more than twothirds of new positive tests being the U.K. variant.

After putting two provinces and some 50 towns on a modified lockdown, Lombardy’s regional governor announced tightened restrictions Friday and closed classrooms for all ages. Cases in Milan schools alone surged 33% in a week.

Reasons for hope

WHO’s Kluge cited Britain’s experience as cause for optimism, noting that widespread restrictions and the introduction of the vaccine have helped tamp down the variants there and in Israel. In Britain, cases soared in December and triggered a national lockdown in January. Cases have since plummeted, from about 60,000 a day in early January to about 7,000 a day now. The British government says it will tread cautiously with plans to ease the lockdown.

That process begins Monday with the reopening of schools. Infection rates are highest in people ages 13 to 17, and officials will watch closely to see whether the return to class brings a spike in infections.