Fun fact: Jupiter. Saturn and Mars all had a conjunction on 24th of March, 1345, right in the middle of the Black Plague. One of my hobbies is reading about plague, especially the Great Plague of the 1340s that killed, on average, 1/3 of Europe.
Guess who died the most? People who couldn't think logically and could not see the link between the filth everywhere, and the disease. Filth attracts rats, which carry the fleas, which carry the bacterium. Fleas jump off the rats and get into the peoples' bedding, where they bit the people and transmit the plague.
An occasional walled town here and there in Europe had enough common sense to lock down their gates completely during the plague, and do it early enough, and had the fewest percent of casualties. But these towns were rare. Poland fared a bit better because, the books say, it was surrounded by mountains and it was hard for traders to get there (with rats on their wagons).