When Rio Grande Valley retiree Robert Chapa finally got his COVID-19 vaccine in March after months of trying to secure an appointment, it was a nearby school district that came through for him. After a year of living in a national hot spot for the virus, where death rates at one point were among the highest in the nation, Chapa, 59, was anxious to get the shot. “I was at high risk, with one kidney,” said Chapa, who lost the organ in a car accident decades ago. “I stood in line for three hours, I think. But if you gotta get it,