Contagion (PHB, p. 227) has always been a powerful spell.
It used to be unclear, by RAW, what happened during the three (or more) turns a target was making saving throws. The original spell description said:
Your touch inflicts disease. Make a melee spell attack against a creature within your reach. On a hit, you afflict the creature with a disease of your choice from any of the ones described below.
At the end of each of the target's turns, it must make a Constitution saving throw. After failing three of these saving throws, the disease's effects last for the duration, and the creature stops making these saves. After succeeding on three of these saving throws, the creature recovers from the disease, and the spell ends.
Now an errata has clarified (bold added):
The last sentence of the first paragraph now reads, “On a hit, the target is poisoned.” The second paragraph now reads, “At the end of each of the poisoned target’s turns, the target must make a Constitution saving throw. If the target succeeds on three of these saves, it is no longer poisoned, and the spell ends. If the target fails three of these saves, the target is no longer poisoned, but choose one of the diseases below. The target is subjected to the chosen disease for the spell’s duration.”
This is a helpful addition: being poisoned imposes disadvantage on attacks and ability checks, so it's a useful spell even before the disease takes effect. But this raises a confusing question for me: dwarves have the following racial trait (PHB, p. 20):
Dwarven Resilience. You have advantage on saving throws against poison [...]
Does a Dwarf have advantage on Contagion's saving throws now?
It might seem obvious that they would, especially since creatures immune to poison are definitely immune to any effects of Contagion. But I wasn't sure if these saving throws were "against poison", since failing three saving throws doesn't inflict the poisoned status: the melee spell attack did that. In fact, failing the saving throw three times will remove the poisoned status (the same as succeeding at the saving throw three times).
So then how does this work?
Given that the poisoned condition isn't contingent on failing the saving throw, does the saving throw for Contagion now count as a "saving throw against poison"?