. Landscape architect Scheri Fultineer walked out of the white vaccination tent at Massachusetts General Hospital with a Band-Aid on her shoulder and a feeling of delight at how easy it was. "Earlier in the year," she said, "I was not optimistic." In mid-February, just as eligibility expanded to everyone 65 and older, the state's sign-up website crashed, so infuriating Gov. Charlie Baker, R, that he publicly fumed, "My hair's on fire." Across the U.S., such out-of-the-gate stumbles have been righted and then some. Massachusetts' vaccine effort is moving so quickly that almost 38% of residents have received at least one dose, and the massive new system for getting shots into arms has plenty of untapped capacity.