IT'S A SOUL THING not so much a physical body thing - or at least that is how I intend to play it until canon tells me different, but yeah the implication is that the Angel contaminated some of her soul when it hijacked EVA-03 while she was still in it. (OOPS SPOILERS?) Which is why NERV didn't just out and out let her die or dispose of the body after EVA-01 got ... done ... biting everything to death ... so it doesn't affect her physical body at all, I guess, but there's "residue" left.

... oh that won't be unfortunately reminiscent of the Organization's thoughts about yoma/claymore at all ... g-good times ...

yes, totally safe, just like i'm just a cheerful loli with a sword