I was able to track down the original curse ritual. There are some ingredients needed that I wasn't able to find, but you may have a source I don't. Nothing else came up about vampires with souls without the spell.
SEVEN HELLS IT HURTS. A BLOODY SPRAINED ANKLE, BROKEN RIBS AND A BROKEN ARM!? I AM A WAR HERO! I DEFEATED THE NIGHT KING! INJURED OR NO, I WILL NOT STAY IN THIS BED, DO YOU HEAR ME?! I NEED TO BE BACK IN THE THICK OF IT!