With a surge in coronavirus cases straining health systems in many European countries, Greece announced a nationwide lockdown Thursday in the hopes of stemming a rising tide of patients before its hospitals come under “unbearable” pressure. Greek Prime Minister Kyriakos Mitsotakis said that he acted before infection rates reached the levels seen in many neighboring countries because, after years of financial crises that have damaged its health system, it couldn’t afford to wait as long to impose restrictions as others had. Britain’s own lockdown kicked in Thursday, shuttering restaurants, hairdressers and clothing stores until at least Dec. 2. The lockdown decision was an about-face for the government, which had earlier advocated a targeted regional response to the pandemic. Italy, too, has held off on a nationwide closure, but the government announced that four regions will be put under “red-zone” lockdown for at least two weeks starting Friday, with severe limits imposed when people can leave home. Germany and France have also put some kind of shutdown into effect over the past week.