Vials in boxes containing the Pfizer-BioNTech Covid-19 vaccine are prepared to be shipped at the Pfizer Global Supply Kalamazoo manufacturing plant in Kalamazoo, Michigan on December 13, 2020. – The Pfizer-BioNTech Covid-19 vaccine was to begin leaving the company’s Michigan factory on Sunday, ready to be injected into the arms of millions of the most vulnerable Americans as the global death toll topped 1.6 million.