Why you can't compare Covid-19 vaccines What a vaccine's "efficacy rate" actually means. 2021-03-20 19:00:00 - Vox More Posts Be Smart | The Biggest Myth About Innovation Gene Kelly | Singin' in the Rain (1952) Nick Crowley | Smartschoolboy9: An Internet Rabbit Hole Cheap vs Expensive Phones | How Close Are They!? Italy | Florence | Complete Walking Tour