In fact, as long as cats don't go out and don't come into contact with other animals, even if they haven't been vaccinated, the probability of suddenly getting the cat plague is very low. Although in theory, the cat plague virus can be stained on the soles of people's shoes and brought into the house, people basically change into slippers as soon as they enter the house, and the outdoor shoes won't have their soles facing up. Cats have all kinds of quirks, but cats that like to lick the soles of their shoes are still very rare, so this route of infection only exists in theory.
Bacterial gastroenteritis was far more common than cat plague because cats liked to lick things randomly. They licked their own fur, their buttocks, and after that, they licked their owners. It was normal for bacteria to enter their bodies. Bacteria were everywhere, but the virus was not everywhere.