Several sources are reporting that Novartis and Merck are in discussion to trade select operations. A deal could shift Novartis’ animal-health and human vaccines units to Merck and send Merck’s OTC healthcare unit—including Coppertone—to the Swiss based drug firm, which operates in the US from a headquarter in Greensboro, NC.   Merck’s OTC business includes Claritin allergy medicine, which analysts see as a perfect fit for Novartis, which sells products like Triaminic, a cold medicine, and Lamis...