Adults who received the updated coronavirus booster shots are better protected against severe disease than those who haven’t, cutting their risk of having to visit an emergency room or being hospitalized with covid-19 by 50 percent or more, according to new federal data.Two reports released Friday by the Centers for Disease Control and Prevention give the first detailed look at how well the updated boosters from Pfizer and Moderna protect against serious illness. But uptake of the “bivalent” boosters rolled out in September has been low among vaccine-weary Americans, with only about 14 percent of those eligible — ages 5...