<qa>  What is the purpose of the present dose ranging study?The aim of the present dose ranging study is to evaluate the safety, tolerability and immunogenicity of two doses of twelve different formulations of a Cell Culture-Derived H5N1 Subunit Influenza Virus Vaccine, adjuvanted with MF59 or non-adjuvanted, given three weeks apart and followed by a booster dose after 12 months in healthy adults 18 to 40 years of age. 