“WE’RE bringing health care to where people live and work.” So declared Larry Merlo, chief executive officer of CVS Health, an American retail-pharmacy giant, on December 3rd, announcing a $69bn deal to buy Aetna, a health insurer. The deal is worth some $77bn after CVS’s assumption of Aetna’s debt, and is due to close in the second half of next year. Shares in both firms fell on the news, perhaps because the deal is likely to yield results only over the long term.