Moderna co-founder Noubar Afeyan concedes that there is plenty he still doesn't know about his company's COVID-19 vaccine, just as there's plenty he still doesn't know about the virus. But he is confident about one thing: "I view the vaccine as the best mask. It's a molecular mask, and once we have it onboard once, then presumably it will protect us." His conversation with Ian Bremmer was part of the latest episode of GZERO World.

Watch the GZERO World episode: A Shot in the Arm: Moderna's Co-Founder on the COVID-19 Vaccine