Advertisement Whenever I talk to people about vaccines, the same questions come up over and over again: have we tested them for long enough? And how do we really know they are going to be safe, long term? It seems like a compelling point. The first vaccine trials started about 16 months ago. Sure, we can be confident in their short-term safety … but how do we know in a decade or two we’re not going to start turning into horrifying lizard creatures? The answers are surprising. Vaccine trials are shorter than you might think – but time and time again, they produce safe and effective vacc...