Part I: Intramuscular (i.m.) vaccination of a single dose of 0.1 µg, 0.3 µg, 1 µg, 2 µg, 3 µg, 5 µg and 8 µg of STF2.HA1 (SI) (VAX125) to be given on Day 0~Part II: Intramuscular (i.m.) vaccination of a single dose of placebo or one of two dose levels of STF2.HA1 (SI) (VAX125) (optimum dose levels to be determined from the safety and immunogenicity data from Part I of this study) to be given on Day 0~Part I Primary: To assess the safety, reactogenicity, and tolerability of the VAX125 vaccine delivered i.m. in a single dose regimen of dose levels of 0.1 µg, 0.3 µg, 1 µg, 2 µg, 3 µg, 5 µg, and 8 µg in healthy adults 18 - 49 years of age, inclusive.~Secondary: To assess the immunogenicity of the VAX125 vaccine delivered i.m. in a single dose regimen at dose levels of 0.1 µg, 0.3 µg, 1 µg, 2 µg, 3 µg, 5 µg, and 8 µg, for inducing a post-vaccination serum HAI antibody response in healthy adults against the influenza A virus H1 HA.~Part II Primary: To assess the safety, reactogenicity, and tolerability of a single dose of the VAX125 vaccine delivered i.m. in one of two dose levels as compared to placebo, (optimum dose levels to be determined from the safety and immunogenicity data from Part I of this study), in healthy adults 18- 49 years of age, inclusive.~Secondary: To assess the immunogenicity of a single dose the VAX125 vaccine delivered i.m. in one of two dose levels as compared to placebo (optimum dose levels to be determined from the safety and immunogenicity data from Part I of this study) for inducing a post-vaccination serum HAI antibody response in healthy adults against the influenza A virus H1 HA antigen.
Is VAX125 safe at doses ranging from 0.1 to 8 ug when delivered i.m. in a single dose regimen Is VAX125 able to induce a post-vaccination serum HAI antibody response in healthy adults against the influenza A virus H1 HA.