An Old World vampyre is one who has been turned (began life as a human, but is now a vampyre). These vampyres are generally sanguinarians, not psionic vampyres. They need to feed far more often than a New World vampyre, and they need larger quantities of blood. Old World vampyres are also either human-blood drinkers or animal-blood drinkers, and they cannot tolerate the other type.
New World vampyres are beings who were born vampyres. These vampyres were usually Old World vampyres in a past life(lives). Unlike Old World vampyres, New World vamps vary. Some are sanguiarians, some are psionic, and a few are able to feed off of either. They also have the ability to feed off of either human or animal blood, though most will have a taste preference.
There are far more New World vampyres than Old World vampyres for a very simple reason. Vampyres are usually attracted to other vampyres. After all, who understands the thirst better than another vampyre? However, Old World vampyres are sterile, and even if they could produce offspring, those offspring would be New World vampyres, because they have not been turned. Few vampyres know how to turn a human (no, the Interview With a Vampire way doesn't work, neither do any of the other 'Hollywood' methods), and those who do have no desire to undertake the process.
New World vampyres, on the other hand, are just as fertile as anyone else. They often produce offspring, and these offspring are New World vampyres as well. Though some diapprove of generating more vampyres, it is my belief that the more vampyres there are who were brought up to accept who we are, the less misunderstanding and problems we would have.
