0% probability
Running some real calculations for Isolde, I'm coming up with 0% Pi with FFP2's. Expected cases are also 0.00 - for 2 people, so Pi is < 0.005
Appealing as it is, I don't think 0% risk is a good way to communicate this. We could add a couple of decimal places and for anything less than 0.045, we round it up to 0.01 as an imposed minimum.