The classic vampire as we know it is a symbolism mainly for diseases in (eastern European) medieval times. The Chinese Jiang Shi or the Greek Lamiae are often associated with the typical medieval eastern European definition of vampires, but it definitely has its differences. Garlic helps against the "vampire" because it is highly antibacterial. Often, people would slam their doors shut when they'd hear about the sight of a "vampire" near the village. Coincidentally this is pretty much what people did when they heard of the plague
outbreaking and having struck people nearby. Post-mortem growth of nails and hair and a variety of sounds actually caused by the slow decomposition of the body (it's disgusting but that's reality, haha) were the main reasons why (naive and brainwashed by the church with no ability of critical thinking) people saw "vampires" in some of their newly deceased and made sure to decapitate them, ram a stake into their heart etc. - probably without any effect against these unpleasant noises, but anyway.. ;) Rabies are often linked to "vampirism" too.
So, while i love Castlevania, it is crucial (ha! see what i did there) to know that Yeshua and YHWH and making a cute cross with your fingers won't help against diseases, but apparently silver weapons do help against "vampires" because *drum roll* they have an antibacterial effect too! By that time, church already destroyed the knowledge of purifying water along with the "witches" and "warlocks" aka. the native European healers who knew it. Instead of drinking water from copper or silver containers, shit got SACKED - copper and silver dishes and cutlery was widespread before, now people were cucked into drinking wine and beer all the time, being told their water is polluted and that there is no safe way to drink it. Scandinavia, to this day, still suffers from the aftermath of having everyone drink alcohol instead of purified water, and alcoholism actually "runs in families". You could almost say the church GAVE people "vampirism".
PS: A more modern association with vampires is that of AIDS. Coincidentally this is a disease too, even a "disease of the blood".
"Results of E. coli O157:H7 destruction on an alloy containing 99.9% copper (C11000) demonstrate that this pathogen is rapidly and almost completely killed (over 99.9% kill rate) within ninety minutes at room temperature (20 °C).
At chill temperatures (4 °C), over 99.9% of E. coli O157:H7 are killed within 270 minutes. E. coli O157:H7 destruction on several copper alloys containing 99%–100% copper (including C10200, C11000, C18080, and C19700) at room temperature begins within minutes. At chilled temperatures, the inactivation process takes about an hour longer. No significant reduction in the amount of viable E. coli O157:H7 occurs on stainless steel after 270 minutes."
IIRC, there are quite some cultures (i think parts in India too) where people give copper (or was it silver? i can't really remember, excuse me) plates and cutlery as a gift to newborns. This may look silly nowadays, especially if one doesn't know the reasoning behind, but in older times this probably was something like a "level 1 life insurance" and i'd deem it to be lovely if friends and family want to help protecting my baby from bacterial infection :)
Correction, finger nails, hair etc. does not continue to grow after death, it simply may appear to do so: