The secret behind medicine that uses messenger RNA (or mRNA) is that it "teaches" our bodies how to fight diseases on our own, leading to groundbreaking treatments for COVID-19 and, potentially one day, cancer, the flu and other ailments that have haunted humanity for millennia. RNA researcher Melissa J. Moore -- Moderna's chief scientific officer and one of the many people responsible for the rapid creation and deployment of their COVID-19 vaccine -- takes us down to the molecular level, unraveling how mRNA helps our bodies' proteins maintain health, prevent disease and correct errors in our genetic code. "We have entered an entirely new era of medicine," Moore says.