In cell culture-based vaccine production, scale-up of adherent cells is challenging. This study shows a process for scaling up adherent Vero cells from static cell factories to influenza production at 50 L scale using WAVE Bioreactorâ„¢ systems and ReadyToProcess singleuse equipment. Vero cells were grown to high cell density on Cytodex microcarriers in 10 L working volume. The cells were detached with trypsin and used to seed a 50 L production culture with the same microcarrier concentration. The cells were allowed to reattach and grow on the new microcarriers in a larger Cellbagâ„¢ bioreactor chamber. Cells were subsequently infected with influenza virus. The results show a repeatable scaleup procedure.