[Introduction to novel vaccine adjuvants and their role in influenza vaccination]

New vaccine approaches based on subunit vaccines and on highly purified recombinant proteins use adjuvants to compensate for the loss of immunostimulatory components that are naturally present in whole cell vaccines. The development of adjuvanted influenza vaccines comprising squalene emulsion adjuvants effective against pandemic influenza strains highlights the contribution of novel adjuvants in increasing vaccine coverage by augmenting protection rates and by affording cross-strain protection and antigen dose-sparing. Nevertheless, the development of new adjuvants remains challenging in terms of quality and safety assurance and in terms of clinical and industrial development costs.