Interesting! I never heard of a plague vaccine before. And I am a professional vaccine expert, I get paid to know this stuff.
Although, from what I can find on Google about it, it looks like the plague vaccine is only administered under very limited circumstances. I guess going somewhere where they barbecue potentially plague infected groundhogs is not one of those circumstances.
Is your travel destination Four Corners? Oops, no, that was hanta.
Anywhere there are sub or tropical forests in Asia, I'd get it. Anywhere in SA, CA or Africa, I'd get it. It hurts and works you over physically but better than the plague.