If you are talking about people who have Photophobia (sensitivity to light) and who crave blood, then yes they can and do exist. However, they are about as powerful as a human in the hospital.
And no, you can't become one, it's a disorder people are born with. However if you have low Iron intake and contract a sickness which irritates the eyes you could have similar syptoms of them.
physical, blood sucking vampires don't exist. like spellchanter said, people with certain disorders like light sensitivity do [good friend of mine has a mild case] but they're human. a psi vampire, a human who can drain a persons energy, are real. you are normally born one though, i've been told however you can train yourself to zap peoples energy, no spell can change you, it takes hard work. while i don't believe there's anything magical to them, Sanguine vampires are real. they are people who choose to live a vampiric lifestyle; dress in black, wear fangs [file their teeth] consume blood, avoid sunlight and so on. it's a lifestyle, not real vampirism. though some do practice blood magic, it's nothing magical that made them that way.
now, in the astral, yes, they are real. you cannot become one though, it's like wanting to become a ghost or a demon, can't be physically accomplished. like demons and spirits you can, in theory, call upon astral vampires to aid in spellwork, similar to Dragon Magick or Fae Magick.
to actually become one, no, not possible, magic is energy found in nature, as such it has the limitations of nature, humans cannot say some works under a full moon and change into something/someone else. magic works to help move the odds in our favour and make life easier for us. as well, a spell doesn't work overnight, you can't light a candle and have it rain money, you need to go out, and pass out a few resumes. effort needs to be put in on your part to help the spell, and to prove to the God and Goddess you are deserving of whatever you cast for. how would someone work at becoming a vampire? even a weight loss spell requires you to change your eating habits and do a few laps to work.
now, you may ask yourself a few things:
why is there so many vampire spells if they don't work?
spellcasters, this coven places everyone in council, so anyone can post anything. someone could of seen an episode of Charmed or Supernatural where a character casts a spell and becomes a vampire. the person then thinks it's real and posts it on SpellsofMagic without knowing what real magic can do verses fantasy magic.
but i met (RandomUser) and they claim this spell worked for them.
welcome to the internet, people lie. get use to it, if you are going to pursue an Occult path, get ready to sift through nonsense. there's no real filter for pagansim since it's so personal, publishers will throw anything occult, doomsday, aliens, mythology based into the 'New Age' category without doing any fact checking mostly because there really isn't one.
i did the spell though and now i crave blood.
it's in your head. i understand how frustrating an answer that sounds, but your mind is more powerful than you could imagine. it's called The Placebo Effect, you're told something will happen and your mind assumes it will. there was an experiment done a while back i read about in Psychology Today Magazine [yes, i'm a nerd, moving on] there was three test groups given pills to enhance their daily performance. a third of the group was given the real pill, another third were given sugar pills, the last third were told they were being given sugar pills. interestingly enough all three groups saw an increase in their strength and mental alertness. point is, if you think something will happen, it will. ever heard of pseudocyesis? it's also known as false pregnancy, when a woman is so determined to have a child, when she wants one so badly, her mind starts to believe it's true and sends signals to her body that she is. the woman can experience morning sickness, little to no mensuration, even lactation. they're not pregnant, it's their mind believing it is.
sorry this was a long post, wanted to cover everything. sorry if i would up upsetting you in any way, but it's the truth. if you love vampires so much, look into astral projection, or becoming a sanguine vampire who studies blood magic, but you cannot become a real physical blood sucking vampire. best to save your time and energy.
FROM A REAL HYBRID...THE FACTS OF A VAMPIRE:
:YOU DONT LIVE FOREVER
AS FAR AS IM AWARE...YOU DONT DIE THESE DAYS FROM LOSE OF BLOOD,BUT YOU DO GET WEAK WITHOUT IT, AND WITH IT.
.IT JACKS MY ADRENALINE UP...ENERGY!...
:PSY VAMPIRE...YES CAN DRAW ENERGY..BUT YOU CANT DRAIN SOMEONE ENOUPH TO KILL THEM. I HAVE FOUND I DRAW ENERGY WHEN IM JUST AROUND PEOPLE AND I DONT MEAN TO...
: NO...THIS IS NOT BULLSHIT
THE GUY WHO HAS A FRIEND IN WHICH THE SMALLEST LIGHT IS BRIGHT TO THEM IS RIGHT..BUT IT WONT BURN US...NEITHER DO CROSSES.