There are several strategies when trying to control coronavirus - ranging from hard suppression to herd immunity. The idea behind herd immunity is to let the virus spread through a population in manageable numbers with the hope that when enough recover, it won't have anywhere else to go. But that relies on humans remaining immune. Today: why a recent yet-to-be-peer-reviewed study has thrown more doubt on the herd immunity theory. Also on this show: * What's the latest with the Russian vaccine? * Is it safe to go back into shopping centres in Melbourne while wearing a mask? And Norman has some research from Nature on our good friend the D614G spike protein mutation, and why it mightn't be worth worrying about too much.