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?