Shopping: The custom of saying “bless you” etc. after a sneeze is at least 1500 years older than that. Also, that was about the black death, which had nothing to do with sneezing. The first major (and biggest) outbreak of the bubonic plague was in the 1300s. Somewhere between 25-50% of the European population died.
Yeshivaguy: It was more than just that they smelled bad. The theory at the time was that the disease spread through smell (they weren’t so wrong, it was airborne). So they all carried fragrant perfumes (sometimes they even wore masks with duck-billed noses full of perfume) to avoid catching the disease from the smell.