In the last few years the rates of vaccine preventable illness have been on the rise. This isn't just something that's happening in the United States – it's happening throughout the world. Often, these outbreaks begin with unvaccinated people. They spread through them, too. Outbreaks occur because of a breakdown in herd immunity. That's the topic of this week's Healthcare Triage. Those of you who want to read more and see references can go here: http://theincidentaleconomist.com/wordpress/?p=57180 John Green -- Executive Producer Stan Muller -- Director, Producer Aaron Carroll -- Writer Mark Olsen -- Graphics http://www.twitter.com/aaronecarroll http://www.twitter.com/crashcoursestan http://www.twitter.com/realjohngreen http://www.twitter.com/olsenvideo