The premise behind this spell is that of a blood bond. So yes, blood would be necessary ... though this spell also completely misses the mark of what a blood bond is. The sentiment of a spell like this might feel almost romantic, but, alas this spell falls into the 'unrealistic' category in regards to ideas of sharing emotions, injury, or death.
Also regardless of the spell itself, Sharing blood in any form is always potentially hazardous. Not only because of communicable diseases but also mundane infection. -Especially- when done by people who are more concerned with being cool or edgy-romantic than they are with using sanitary preparation and post-act cleaning and dressing. For this alone it is a very bad idea. One in need of very serious, very careful critical thinking.
Blood- and especially the mingling of blood- is indeed powerfully symbolic. Blood is representative of genetics, family, and a part of the self representing the whole. It is literally and figuratively the essence of yourself as you are, and the influence of your family line. And a Blood oath/Blood bond is historically representative of expressing total loyalty and recognizing two people as now being considered actual family. Blood was long ago seen as representing one's lineage and genetics/breeding/caste. Sharing Blood made those doing the bonding seen as being both legally and physically becoming brothers. (Or sisters, I suppose) Which extended into responsibilities of finance and honor/legalities such as repaying debts, revenging wrong-doing, and inheritance.
However, nowhere in history shows any connection between Blood bonds and oathbound people directly sharing in injury, death, thoughts (other than being of like mind... as they were before the bond to begin with), emotions, or 'soul link'. Merely that they were now essentially the same as being siblings as if born from the same mother. Or 'of the same Blood'. Likewise, performing a spell like this would be an outward expression of kinship, and at most a combining of karmic paths/lessons. Though even then those who ascribe to the ideas of Karma might argue such a bond was created because it already bound them to be destined to meet and form that close of a relationship. ...But that noodle-baking sidetrack of a spiraling 'chicken or the egg' paradox is an entirely different discussion. Pre-destiny versus free will is always an entertaining battleground.