Has your mum had much contact with the kids before this afternoon? How long has she been sick for? I have heard varying info on contagious periods, from 4-5 days (from onset of cold symptoms) to up to 3 weeks, so you might be able to work out whether there is a likelihood of it being passed on. And as Willow said, the current vaccine is only 85% effective.

Be on the look out for cold symptoms first, and maybe just stay away from any really small bubbas until your mum gets her test back.

I really hope it's not WC or if it is that your family hasn't caught it