H7 Influenza Prime-Boost Regimens in Healthy Adults: Recombinant H7 DNA Plasmid Vaccine, VRC-FLUDNA071-00-VP, Administered Alone or With Monovalent Influenza Subunit Virion H7N9 Vaccine (MIV) as Prime With MIV Boost Compared to MIV Prime With MIV Boo...

Background:\ \- Flu virus that causes disease in birds can sometimes spread to people. It can cause severe illness, even death. Vaccines are used to try to create resistance to such infections. Researchers want to test a new vaccination strategy, combining two different vaccine types, the H7 DNA Vaccine (DNA vaccine) and H7N9 Monovalent Inactivated Vaccine (MIV), to see if one of two combinations offer better protection against a certain type of bird flu in humans when compared to vaccination using two doses of MIV alone. Objectives: * To see if 2 vaccines for bird flu, are safe and tolerable for humans. * To study immune responses to these vaccines. Eligibility: \- Healthy adults 18 60 years old. Design: * Participants will be screened through a separate protocol. * Participants will be randomly assigned to 1 of 3 groups. Each group will get a different combination of vaccines. * Participants will have about 8 clinic visits. Each visit takes 2 4 hours. Blood will be drawn at some visits. Urine samples may be collected. * Participants will receive vaccinations at 2 of the visits, 16 weeks apart. * The H7N9 MIV will be injected in the upper arm using a needle and syringe. The DNA vaccine will be injected in the upper arm using a device that delivers the vaccine through the skin by pressure instead of a needle. * Participants will be observed for at least 30 minutes after each vaccination. * Soon after each vaccination, participants will get 1 2 phone calls, come to clinic for evaluation, and complete a diary at home for 1 week. They will record their temperature and symptoms and look at the injection site daily. * Participants will have follow-up blood tests.