The United States now accounts for one-fifth of all new coronavirus cases globally, with New York at the epicentre with over 150,000 cases. In this episode, special guest Dr Tom Frieden, former director of the Centers for Disease Control and Prevention, shares his thoughts from New York on how to reduce the risk to healthcare workers, why until we find a vaccine we are living in a ‘Covid World’, and on how the world can come out of this crisis a safer place. In the pod this week are New Scientist journalists Rowan Hooper, Penny Sarchet, Graham Lawton and Sam Wong. They discuss the science of baking bread and why you don’t need to buy yeast; how a parakeet has become the world’s most invasive species; the lifespan of the world’s biggest fish, and the surprising things bacteria might be responsible for - including maybe even the weather! To find out more, subscribe at newscientist.com/podcasts. Our GDPR privacy policy was updated on August 8, 2022. Visit acast.com/privacy for more information.