Many of the 64 people affected either fainted or reported dizziness. Some got nauseous or vomited, and a few had racing hearts, chest pain or other symptoms.
In a statement Friday, the two pharmaceuticals said their submission to the European Medicines Agency is based on an advanced study in more than 2,000 adolescents that showed their vaccine to be safe and effective.
In the same breath, however, the speech marking Biden's first 100 days as commander-in-chief offered a measure of comfort by suggesting Buy American would not offend the terms of trade deals like the U.S.-Mexico-Canada Agreement.
Psaki says the U.S. is waiting for approval from the Food and Drug Administration to share 10 million doses "in the coming weeks."
So far, Pfizer's ongoing trial indicates the company's two-dose vaccine remains highly effective for at least six months, and likely longer. People who got Moderna’s vaccine also still had notable levels of virus-fighting antibodies six months after the second required shot.
The U.S. has already provided Canada with about 1.5 million doses of the AstraZeneca vaccine, and gave 2.5 million doses to Mexico.