Silver was never used as a killing device against vampires until recent Hollywood productions. Incidentally... the sun never harmed a vampire until the 1922 Murnau movie Nosferatu. So it is understandable that there's confusion as to what can and can't kill a vampire.
Silver is for werewolves.
But all that's superstition and bogus remedies concocted by religious superstitious people thinking those beings are the product of Satan. They however exist in some form or another in nearly every culture, every religion... so... the assumption they are the spawn of just one... is beyond ridiculous.