Ok, first let me be very clear: I am firmly convinced that all vaccines are greatly over used, and even when they are used correctly, they might not be the best choice.  That said, here is a link to a story about a British student who has perfected a means of maintaining vaccines at the ideal temperature while in transit, that works for up to 30 DAYS.

http://www.bbc.co.uk/newsbeat/article/37306334/this-invention-by-a-british-student-could-save-millions-of-lives-across-the-world

What gets my attention is the possibility that the same tech can be used for transporting organ transplants, camping foods, and a lot more.