Yes Ziggy, they would. There is a study published by Dr. Z Weizman (paediatrician) showing that a once a day dose of Reuteri given to nursery school children of this age resulted in less illness (and in turn less absenteeism, less Dr visits, less antibiotics etc). It is one of the first published studies that shows actual proof of the immune modulating effect of Reuteri.
You can find the reference at www.biogaia.com, look under research or alternatively if you send me an e-mail contact I can send it to you.