On Nov. 15, 2021, AstraZeneca reported that 2 billion doses of the COVID-19 vaccine had been released for supply to date. Despite its extensive experience of vaccine development, the University of Oxford had never manufactured more than a few thousand doses of any single vaccine until 2020.

A paper, published in collaboration with AstraZeneca in Biotechnology and Bioengineering, tells the story of how a key discovery just before the start of the pandemic unlocked the possibility of large-scale manufacturing.