EDIT : nope.

It seemed to me that when Ellie looked at her arm before she got out of the car her bite was way more infected than before. Pair that with the line about still "waiting for her turn" to die, and what I got from this is that she was actually turning, albeit very slowly, and thus not as immune as thought. Those two subtleties basically framed the entire ending for me, but going through the other thread here it seems that very very few others saw this to be the case. Am I totally off here? Or Is Naughty Dog pulling off the ultimate ambigu-ending?

I think you're off. I think the framing of the bite mark is just a bit closer than previous times that they show it, so you get a more detailed look at the bumps and redness, but it isn't more harsh than the first time you see it at the beginning of the game. It's also in a well-lit area compared to the other times you see it (at night and in David's dark holding cell).

Doubt it. A zinger like that would be more explicit than that. Her line about still waiting for her turn is simply how she believes that she's a death magnet.

I don't think that's where Naughty Dog wanted your focus to be when it came to the ending.

The bite mark didn't seem that different to me. And the 'waiting to die' remark implied to me that she was telling Joel 'I'm ready to die' and not so much 'I'm dying.'

She's looking at the bite to show that she has it in her mind to build up the last conversation where she reveals how she was bitten and who she lost. Then telling Joel to swear to her his lie about the Fireflies was true, so the weight of the lie would be on Joel's shoulders and not hers (she knows that what Joel said was complete bullshit, but she knew that he also took her away for a reason).

ah okay, thanks guys. I think I like this more. less dark but still incredibly heavy.

I wouldn't rule out the possibility that she's just progressing slower. I looked at the infection on the arm and initially though it looked different. To be sure you'd have to grab frames from early and late game and properly compare. Having said that, I don't think that's what is happening.

I'd agree that her looking at her arm was just part of the framing for the following conversation. As I've said elsewhere I feel that yes the ending is intentionally ambiguous and that you read into it what you will.

I actually though it looked less infected, like it was further healing.

The bite on her arm didn't look more infected to me. Although I do think this is an opening for a sequel. The infection is currently living in symbiosis in Ellie's body. Maybe a sequel will pick up in the future when she hits puberty and changes in her physiology disrupt the symbiosis therefore making it more urgent for them to find the vaccine to save her.

She's 14 she already hit puberty.