Study Design: This is a Phase I open-label, dose escalation study to evaluate the dose, safety, tolerability, and immunogenicity of VRC-FLUNPF081-00-VP (HA-F A/Sing) vaccine alone or in prime-boost regimens with VRC-FLUDNA082-00-VP (DNA A/Sing) vaccine. The ypotheses are that VRC-FLUNPF081-00-VP and VRC-FLUDNA082-00-VP vaccines are safe, well-tolerated, and induce an immune response to the H2 antigen. The primary objectives are to evaluate the safety and olerability of two different doses of the HA-F A/Sing vaccine alone and in prime-boost regimens in healthy adults. Secondary objectives are related to the evaluation of the immunogenicity of the HA-F A/Sing and DNA A/Sing vaccines in prime-boost regimens.