thats a good point i never thort ov that .... but one other theory of mine is now her blood becomes the cure 

Nah, way to convenient, Silas would have sucked her dry.

but think about it the vile lookd like blood so whats ta say it wornt happn 

I would think so, yes! Therefore I think Katerina should go to New Orleans and offer Klaus her blood, for his protection.

BUT!! It might be that Esther created the loopwhole so tight, that only the blood of the sacrificed doppelgänger would be able to complete the Hybrid transition!

OMG or Julie Plec specifically made Katherine human FOR this reason.You know how The Originals is coming up,if Klaus ever wants to find a way to turn Hayley into a hybrid or he would want to turn his son/daughter into one because they may not be born immortal,Katherine,since she's only free for the time being,could offer a trade.Her blood for her permanent freedom.

ohhh yer thats a good theory i two berlive that klaus wants hayley and is child ta be come hybrids 

I can imagine Katherine doing something like that: Offering her blood to Klaus to make hybrids in return for her freedom.  Even though its really hard for me to imagine Katherine staying human for a long period of time.  She hates being weak and voulnerable.  But then I think to myself...why would they waste basically ALL of season 4 talking about this cure only to give the only dose of it to Katherine, and then Katherine turning herself back into a vampire...doesn't make sense to me.  So IDK this will be interesting to see. I CAN'T WAIT!

i think a sideaffect of taken the cure will be that she cant be turned back in to a vampire