PARIS/BERLIN (Reuters) - European officials warned against COVID-19 complacency on Thursday and said measures to control a surge in infections as winter approaches must continue despite hopes that new vaccines can bring the pandemic under control.This week’s announcement by Pfizer Inc of a potentially effective vaccine spurred optimism that an end to months of crisis could be in sight, sending financial markets soaring and fuelling public longing for a nearly normal Christmas. But health authorities and leaders across the region urged people to continue complying with lockdowns as it became clear that vaccines would not come soon enough for many COVID-19 sufferers and shrinking economies. “It would be irresponsible to soften the lockdown now,” French Prime Minister Jean Castex told a news conference, warning that, despite signs of a slowdown in infections, gains were fragile. France has the highest number of cases in Europe. “The pressure on our hospitals has intensified enormously,” Castex said, adding that lockdown measures imposed at the end of October would continue until at least Dec. 1.