To evaluate the interchangeability of quadrivalent and bivalent vaccines a randomization will be performed in the group of girls aged 14-15 years who have been assigned at the beginning of the project with extended vaccination scheme (0-6-60) with the bivalent vaccine, so that one third of this group will receive the bivalent vaccine, another third will receive the quadrivalent vaccine and the remaining third will no longer receive additional doses.