Jeannie Hall-Harris did a lot of praying going into Tuesday’s mass-vaccination event in Monroeville. “I was hesitant at first,” she said, moments after receiving her first dose of Pfizer’s covid-19 vaccine. She was one of 5,100 people who received the shot at the Monroeville Convention Center, which partnered with Allegheny Health Network and the Monroeville Area Chamber of Commerce for the event that was scheduled for 8 a.m. to 6 p.m. Hall-Harris of Penn Hills is 65, which puts her in Phase 1A, the state’s first wave of people who qualify for the vaccine. She said she also has high blood pressure.