We tried a Daycare Defence (30 day thing) and Pentavite and in reality it didn't stop anything, we started after DD's second bout of Croup, which was only a fortnight after the first, and she got another 7 respiratory infections over the rest of the year and numerous colds, so I don't hink for us it made any difference, so we are just going with the fact that she should have a better immune system this year