Looks like Alyssa Ashcroft has the T-virus exposure slowing down your aging process-thing that happened with Jill and Wesker.

Been seeing weird speculation that Wesker is supposed to be resurrected in this entry.... and an even weirder theory that he's Grace Ashcroft's bio-dad. /rubs temples/

I'm thinking Grace simply inherited something from her mother, due to Alyssa's exposure to the T-virus.