The Covid-19 delta variant may account for a quarter of new cases in some parts of Italy, a startlingly rapid rise for the virus mutation, a new study shows. The variant, first detected in India, has sent health care officials across Europe scrambling to respond, with some countries rethinking ambitious plans to reopen their economies. Up to 25% of total cases in some Italian regions are linked to the delta variant, up from just 1% registered on May 18, daily Corriere della Sera reported Thursday, according to Pietro Forestieri, president of Ceinge-Biotecnologie Avanzate institute in Naples. “We need to be prepared ... (full story)