The Covid-19 pandemic has ravaged Latin America, killing more than 300,000 people, erasing years of social and economic gains and plunging millions back into poverty. But from Mexico to Brazil, a recent slowdown in new cases and fatalities is raising cautious hopes that the hard-hit region might be turning a corner. While the U.S. has struggled with an increase in new Covid-19 cases over the past two weeks, Brazil has seen a reduction of more than 40% since July. Brazil’s daily death toll, though still one of the…