Board Thread:False Info and Speculative Discussion/@comment-3427796-20140820053526/@comment-4091815-20140820214123

Throughout season 2 and even in the speech by Peter her immunity was treated as it's own, very rare, and separate thing.

You are correct, I believe, that they never did come right out and say it which suggests they could expand the immunity to all Banshee at some point future.

As of now though, we don't have enough cases of immunity to judge and it hasn't come up yet with the other Banshee on the show.