The logo for Merck is displayed on a screen at the New York Stock Exchange on Nov. 17, 2021.Merck on Thursday said its experimental treatment designed to protect infants from respiratory syncytial virus showed positive results in a mid- to late-stage trial, bringing the company one step closer to filing for approval of the shot. The pharmaceutical giant could emerge as a new competitor in the market for treatments against RSV, which causes thousands of deaths among older Americans and hundreds of deaths amo ...