The White House on Tuesday told states to prepare to vaccinate children as young as 5 by early November, even though the U.S. Food and Drug Administration hasn't yet authorized Pfizer's COVID vaccine for children under 12, and despite safety concerns expressed by scientists and pediatricians.

In a private phone call Tuesday with the nation's governors, the White House told states to prepare to vaccinate children as young as 5 by early November. A White House official said the call was made in anticipation of Pfizer's COVID vaccine being cleared for Emergency Use Authorization (EUA) in the coming weeks for children ages 5 to 11.

According to NBC News, the Biden administration purchased 65 million pediatric doses of the Pfizer/BioNTech vaccine — enough to vaccinate an estimated 28 million children who would be eligible should the U.S. Food and Drug Administration (FDA) approve Pfizer's request to vaccinate the younger age group.

In anticipation of a green light from the FDA, the administration began planning vaccination efforts with states, pharmacies and medical groups. The administration told providers in a planning document last week the vaccine for children will be delivered to thousands of sites within one week of FDA authorization.