I also know a couple that have little contact, though they did know each other for many years beforehand. Either way, it's true that a couple could join and stay together regardless of physical intimacy. For some people it is hard to imagine, but it does happen. Love may be receptors in the brain triggered with dopamine, but that doesn't make it less potent. So, with the assumption that Ellie would infect a person, she may still find romantic happiness. Frankly, her odds are probably higher than we might think, because the selection is limited in the fungi-apocalypse.
Besides, we all know how awesome Ellie is as a kid. She's going to be an even more awesome adult woman.
Originally, I thought Ellie and Sam were going to be a thing; of course this idea was canned before too long.
I agree with the theory of: along their journey they shared drinks and such. I mean there's not a lot of time to gripe about "Joel, I don't want your boy cooties, get me my own drank."
Did anyone notice how Joel hesitated to do mouth-on-mouth on her? When we got to that badly flooded tunel, I already suspected she would drown and Joel wouldn't be able to do the mouth-to-mouth. It was awesome.
And when he did hesitate, I was like... holding triangle: "Revive her, damnit!" (jk)
My guess is that her blood is infectious, so she could transmit it by unprotected intercourse. Her saliva may be infected, but would probably not infect someone by kissing, because the 'bugs' would be digested. But I do think her saliva could infect someone if it would enter the blood stream, so... yeah... I guess she has a lethal bite.
Her supposed condition reminds me of Rogue, from X-Men.