We now know why US cannot share its Covid vaccines with the world. Trump WH had forced legal contracts that blocks US doses by Pfizer, Moderna, AstraZeneca, J&J from being donated
The Government may not use, or authorize the use of, any products or materials provided under this Project Agreement, unless such use occurs in the United States or U.S. territories.
Biden administration found a loophole and are only able to loan limited amounts, which they have done for Canada and Mexico .