The Black Plague disappeared without a vaccine

Because all the people that had it died and got burned.

the world was in a solar minimum all the rats moved inside things started warming up rats moved out, thats what ended it dah.And it never disappeared.

Its a seasonal event

Treat your cats well, folks.

Yeah..after killing 75% of Europe. M-o-o-n, that spells "pandemic," laws yes.

Actually I heard an interesting theory floated once: the plague sowed the seeds for the rise of democracy and capitalism. Because it killed so many people, labor was scarce, and big land-owmers had to treat their peasants better and pay more for labor (supply and demand). People who had been living in little shacks were able to upgrade to the bigger houses of better-off people that had died. People weren't dependent on electricity, advanced machines, or other modern technology, so the survivors could just pick up their lives where they had left off, with greater wealth (taken from the dead) and more land.