This study is an extension to Study ALT-103-201, a Phase 2a, randomized, double-blind, placebo-controlled trial to evaluate the safety and immunogenicity of NasoVAX in healthy adults 18 to 49 years of age.

This study is an extension to Study ALT-103-201 to evaluate immunogenicity of NasoVAX administered by intranasal spray at a single dose of 1×1011 vp at Day 366 (± 60 days). Up to 15 subjects who received NasoVAX at the 1×10(11th) vp dose in Study ALT-103-201 will be screened, and a serum sample will be collected from each eligible subject for evaluation of influenza HAI assay against influenza A/California/07/2009(H1N1), a strain homologous to the one used for NasoVAX (monovalent AdcoCA09.HA). Ad5 antibody neutralization assay may also be performed.

Inclusion:

1. Receipt of NasoVAX at the 1×10(11th) vp dose in Study ALT-103-201
2. Adequate venous access for phlebotomy
3. Provision of written informed consent

Exclusion:

1. Any medical, psychiatric, or social condition or occupational or other responsibility that in the judgment of the Investigator would interfere with the subject providing an adequate blood sample or the subject's ability to give informed consent

All subjects who were previously randomized to the 1×10(11th) vp NasoVAX group in Study ALT-103-201