Immunity question

[atadeadrun]

Is immunity reduction story-linked now? All previous references I can find are to the changes that de-linked immunity directly from the bars, but now I've had it drop on entering Noah's hideout a couple times. I never really got that far in the game the first time I played it, but if it's just "Now you're vulnerable to disease because story progression," that's a very different game than I played when I first got it. I also can't find any measurement of immunity short of "high/medium/low," and the in-game database says it's irreversible, happens over time and is unstoppable.

[Sairi (Jen)]

It is story linked. There are certain points in the story where your immunity drops from high to medium and finally low, you'll get notified when this happens.
There are ways to temporarily boost your immune back to high after you visited the first underdust location