Tucked in the Tuscan hills around Siena in Italy, a research lab has come up with an antibody treatment for Covid-19 that its developers say will be 80 times more potent than the one given to former US President Donald Trump in his most critical days in hospital last year.The therapy is derived from the blood of people who’ve recovered from Covid, and relies on 453 different antibodies. It will also be administered as a single shot rather than a drawn-out infusion, which has been the norm for similar drugs. Clinical trials of about 3,000 doses produced so far started in Italy Thursday, and a roll out for general use could be approved as early as this summer. ...