5 Min Read LONDON (Reuters) - The European Central Bank will this week face more questions about an increasingly challenging outlook only a month after it unleashed fresh stimulus to bolster the euro zone economy. FILE PHOTO: The headquarters of European Central Bank (ECB) is photographed n Frankfurt, Germany, January 14, 2021. REUTERS/Kai Pfaffenbach/File Photo Policymakers boosted emergency bond buys by 500 billion euros ($607 bln) in December. But resurgent COVID-19 cases, new restrictions on activity in countries including Germany and France and the slow roll-out of vaccines has cast doubt over the pace of the region’s recovery. “At this point in time, the ECB still finds itself a little bit with its back against the wall,” said Althea Spinozzi, fixed income strategist at Saxo Bank Group. “There’s no alternative but to keep supporting the economy until an end to downside risks are clear.”