For flu I've not heard of any plans to do so but it's a question I can ask. They have done it for covid and polio I know that much. I would presume as the flu surveillance program is so well established using clinical samples, it might be deemed unnecessary to test waste water?

Although from my own point of view, we actually don't get the full picture of how much flu/what types of flu etc are out there globally in a season because we only get clinical samples (I say only, we get thousands of them!). How many people are actually sick with flu, but don't need medical attention, thus not getting swabbed? It is something I've brought up in general discussion and there was agreement, but currently not much we can do about it.