To some extent, experts say, Europeans are paying a price for living in open, affluent democracies, where people are used to free movement, easy travel and independent decision-making, and where governments worry about public opinion. Governments aren’t used to giving harsh orders, and citizens aren’t used to following them.

But China acted with a severity and breadth that stunned the West, making unpopular moves and accepting deep economic damage as the price of containing the disease. It closed off tens of millions of people, prohibiting them from leaving their cities and even their homes, except to get food and medical care, and it imposed lesser restrictions on hundreds of millions, shutting down whole industries in the process.

“China has been willing to go to pretty extraordinary lengths, using the army, using the police, locking people in their homes, using drone technology to monitor behavior, setting up roadblocks,” said Dr. Arthur L. Reingold, head of the epidemiology division at the public health school of the University of California, Berkeley.