Good Morning! Dsii, I guess the only way to avoid is to emphatize on hygiene. Anyone child could have got it and it remain in the body, not displaying any symptoms. Incubation period. Rather then make them skip class when they are well, just let them go with the flow. If really strikes, then compulsory 'stay at home children' lor. hahaha.
Btw, I have the following for free,
a. 3 Shop & save August stamps,
b. booklet of NDP vouchers, I think I took, flyer, night safari, popular and k box.
I think most of the vouchers expire 31 August. Still have lots left i.e. birdpark, gnc, fotohub,osim, hp and electronics etc.
Any one keen and dare to collect from me? hahaha.