There’s loads of really interesting stuff about where the vampire ‘myth’ came from. Obviously there are lots of tales about Transylvania and Vlad the Impaler drinking peoples blood and stuff, but there’s a lot more realistic stuff too.
For example, the symptoms of rabies kind of match up to what the original conception of a vampire (not the modern day sparkly-warkly or dracula type ones) looks like. The disease can cause personality shifts, make people violent, change their sleep patterns so that they become nocturnal, can bring about a drive to bit others and froth blood at the mouth.
There’s also stories about people testing for rabies by seeing if someone could recognise themselves in the mirror, and the fact that people with rabies tend to be hypersensitive, so strong flavours (like… garlic!) would annoy them as well as being averse to light.
Just so happens that vampire bats often carry rabies!
There’s of other stuff about people accidentally being buried alive because they were thought to be dead but actually just in a coma or something and then “rising from the grave”.
Ultimately though, all the folklore points to the vampire myth coming about because of incomplete medical knowledge. It’s really interesting to read and hear about, but means that vampires probably aren’t real.