CAMBRAI, France (Reuters) - Anesthetist Caroline Tesse cannot say whether the third wave of COVID-19 infections sweeping across France will peak in three weeks or three months. But she does know that it is too late to prevent the virus from overwhelming her intensive care unit. All bar one of the ward’s 22 beds is occupied by a COVID-19 patient. The moment a bed is freed, another gravely ill patient is wheeled in - and as the B.1.1.7 variant, first detected in Britain, tightens its grip, they are arriving younger and sicker. “What’s difficult is not having any light at the end of the tunnel,” said Tesse, a 35-year-old mother-of-three for whom the intensity of the latest surge in coronavirus infections is taking a toll at home and in the workplace. Cambrai in northern France lies in one of the hardest hit areas of the country. Some 450 in every 100,000 people are testing positive and the rate is climbing. On the ICU ward, the pace is relentless. Adryen Bisiau, a doctor on Tesse’s unit, described the latest spike as “the toughest wave we’ve endured so far”. President Emmanuel Macron tightened COVID-19 restrictions in much of northern France and the Paris region a week ago, but he stopped short of a full lockdown that many hospitals had been calling for. Strict confinements and school closures should be an act of last resort, Macron and his government say. But on the front line in the battle to save lives, that moment has for many passed. “I don’t think the latest measures can stem the spread,” Tesse said after a delicate procedure to intubate yet another patient. “It’s too late.” “We can’t even tell how long this wave will last.” After a European Union summit at which leaders agreed to stricter export controls on vaccines, Macron on Thursday defended his decision not to impose a third lockdown as early as January. “I have no mea culpa to make, no regrets,” the president said.