Of course they have changed ! It was kinda obvious that this will happen sooner or later, because, reasons:
They are the main couple so by the gods (authors) they have to be together. In this case since Dragosh is the different one Ivo had to change. Check
Ivo almost died, the creature from chap 3 landing a ethereal attack on him. We can conclude that a near death experience happened to Dragosh too if we take what he said. Check
The "Gate Of Spirits" Dragosk could go throught them and he is still 'alive'. Then he subjected Ivo to the same experience, liquid - Ivo still alive (chap4 p9) Check
Then came the mysterious medicine of legend that healed him and was also ingested by Dragosh at some point (p 16) Check
Oh yea and not in the last place, my favourite, exposure to Dragosh and his fluids. Not only was he in constant proximity of him he also contacted his fluids and that is the fastest and easiest way to catch something, be it a virus or, something else . . . Check
It would have been more of a surprise if something like this wouldn't have happened ^-^
PS: I love the name Dragosh, I have this name in my country and I was so shocked to see it, but we actually have a letter for the 'sh' sound it's ș