that its COVID-19 vaccine is safe and strongly protective in kids as young as 12, a step toward possibly beginning shots in this age group before they head back to school in the fall.Most COVID-19 vaccines being rolled out worldwide are for adults, who are at higher risk from the coronavirus. Pfizer's vaccine is authorized for ages 16 and older. But vaccinating children of all ages will be critical to stopping the pandemic -- and helping schools, at least the upper grades, start to look a little more normal after months of disruption.In the vaccine study of 2,260 U.S. volunteers ages 12 to...…that its COVID-19 vaccine is safe and strongly protective in kids as young as 12, a step toward possibly beginning shots in this age group before they head back to school in the fall.Most COVID-19 vaccines being rolled out worldwide are for adults, who are at higher risk from the coronavirus. Pfizer's vaccine is authorized for ages 16 and older. But vaccinating children of all ages will be critical to stopping the pandemic -- and helping schools, at least the upper grades, start to look a little more normal after months of disruption.In the vaccine study of 2,260 U.S. volunteers ages 12 to...WW…