More than half of the U.S. adult population is now fully vaccinated against the virus, according to the Centers for Disease Control and Prevention. As of May 26, 129.8 million Americans—including 74.1% of seniors, 50.3% of adults, and 39.7% of the total population—are in that category, up from 125.5 million a week ago. The nation is poised to reach half of the total population with at least one vaccine dose by week's end: 165.1 million people, or 49.7% of the population, currently have received at least one shot.