完整标题： Pfizer COVID-19 shot expanded to U.S. children as young as 12
发稿单位： PBS
发稿时间：May 10, 2021 6:51 PM EDT
原文连结：
https://www.pbs.org/newshour/health/pfizer-covid-19-shot-expanded-to-u-s-chi
ldren-as-young-as-12
继加拿大开放后，美国也接着开放了