Immunogenicity and Safety of Varying Dosages of a Monovalent 2009 H1N1 Influenza Vaccine Given With and Without AS03 Adjuvant System in Healthy Adults and Older Persons

Background. Adjuvanted vaccines have the potential to improve influenza pandemic response. AS03 adjuvant has been shown to enhance the immune response to inactivated influenza vaccines. Methods. This trial was designed to evaluate the immunogenicity and safety of an inactivated 2009 H1N1 influenza vaccine at varying dosages of hemagglutinin with and without extemporaneously mixed AS03 adjuvant system in adults ≥18 years of age. Adults were randomized to receive 2 doses of 1 of 5 vaccine formulations (3.75 μg 7.5 μg or 15 μg with AS03 or 7.5 μg or 15 μg without adjuvant). Results. The study population included 544 persons