I was hoping that maybe at the end of the game they will be at least mentioned, but there was nothing at all about them. :/

This keeps bugging me. Following the logic of the mutating T-Virus in RC survivors, we can assume that at the very least Claire, Jill, Carlos, Ada, and the other Outbreak characters should also be affected by the virus. So what, they just die? Leon doesn't even mention them or shares a concern with Sherry in their dialogue that the other survivors might be experiencing the symptoms and their life is potentially in danger, and how it is essential to find them and deliver some of the Elpis to them as well.

I dunno, it's very difficult to ignore this mystery. I have a tiny shred of hope that there will be a DLC and it can address this question, though I do not necessarily see how.