Eli Lilly said Tuesday it would buy three early- and mid-stage vaccine developers, a boost for the field.  The deals — which together could cost up to nearly $4 billion — are the latest acquisitions from Lilly, a company rich with cash from its booming GLP-1 business. In recent months, it’s picked up companies working on cancer, autoimmune diseases, and sleep disorders, all for under $10 billion each.  The companies being bought are Curevo, LimmaTech Biologics, and Vaccine Company. Continu