A phase II, randomised clinical trial to demonstrate the non-inferiority of low-dose MF59-adjuvanted pre-pandemic A/H5N1 influenza vaccine in adult and elderly subjects.

Background: Effective planning and preparedness against a possible future A/H5N1 influenza pandemic is a major global challenge. Because dose sparing strategies are required to meet the global demand for vaccine, efforts have focused on the development of adjuvanted vaccine formulations of relatively lower antigen content.

Aim: This study aimed to demonstrate the non-inferiority of a low-antigen-dose (3.