The investigators hypothesize that in those children who received a protein-energy enriched milk during hospitalization the catabolic state will be reversed more quickly by the intervention and will need less hospitalisation days, less oxygen support, less antibiotic use, less re-admission rate, less persistent wheezing and less work days missed by the parents. The investigators also hypothesize that the effects of the nutritional intervention on the proposed outcome parameters will be greater in children screened at high nutritional risk.