Emma Keeling talks to the U.S. scientists behind Corbevax, a patent-free brewed vaccine that's grown in yeast. This technology is far simpler and more readily available than vaccines using MRNA, and could be a potential game changer in making COVID-19 vaccines more available to developing countries. Emma speaks to Maria Elena Bottazi from the Baylor College of Medicine about how the vaccines are made and how pivotal they're already proving to be in India where they are currently being rolled out.