Taison Bell, an infectious-disease physician at the University of Virginia, noted that the rate of blood clots among AstraZeneca recipients was close to the rate you’d see in a normal population. “When we look at the risk of death from COVID-19, long haul from COVID-19, versus these very rare side effects, I think the overwhelming pendulum swings towards getting vaccinated,” he said. “I’m not particularly concerned about this announcement.”