Influenza is a major respiratory disease of pigs. Influenza causes reduction in pig’s performance and is a public health concern given that strains with pandemic potential can emerge in pigs. The main strategy to control influenza in pigs is sow vaccination, which enhances the transfer of maternally-derived antibodies to the offspring. Sow vaccination can reduce the level of influenza in piglets at weaning and we hypothesize that reduction of prevalence at weaning impacts influenza circulation after weaning. In this project, we aimed to assess the impact of influenza prevalence at weaning on transmission, clinical signs and performance in nursery pigs.