The present invention relates to a composition comprising at least one fucosylated oligosaccharide and at least one N-acetylated oligosaccharide(s), for use in preventing and/or treating URT infections in an infant or young child fulfilling at least one of the following criteria: i) the infant or young child is born from a non-secretor mother and/or is fed with a mother's milk deficient in at least one fucosylated oligosaccharide(s) ii) the infant or young child has at least one sibling iii) the infant or young child was born by C-section
