I've got a headcannon that, yes, Vampires don't like garlic. It makes their tongues itchy and uauly does a bit of rash. Not too bad.
Now consider. A human is turned into a vampire. What's special about that? That human ALREADY had a garlic allergy. So anytime a hunter throws garlic at them they're absolutely gagging, puffing up, and losing breath. Yes! This is the moment the hunter kills their first vampire and then the monster pulls out an epipen and stabs it into their leg.
Suddenly the vampire is breathing easier (thank you quick healing) and smacking the hunter upside the head like-
"That could have killed me you idiot!!!"
"That was the point!"
"You obviously aren't a veteran hunter...Garlic doesn't kill vampires."
"It almost killed you."
"Well yeah? I'm ACTUALLY allergic, thank you very much."
"...but...then you were allergic before? You've never had garlic chicken before?"
"...It was an unfortunate happenstance of genetics...Shut up."