BPL-1357 Against H1N1 Influenza Virus Challenge

Background: Influenza (flu) infections are a serious global health threat. Each year, between 3 and 5 million people get the flu, and up to 500,000 die from it. Current vaccines protect against seasonal flus, but broader vaccines are needed to protect against potential flu pandemics. Objective: To test an experimental flu vaccine. Eligibility: Healthy people aged 18 to 55 years. Design: The study will last 5 to 8 months and has 2 phases, A and B. The study vaccine will be given either as a shot in the arm or as a nasal spray. Participants will receive 1 of 3 combinations: (1) study vaccine in the nose and placebo in the arm; (2) placebo in the nose and study vaccine in the arm; or (3) placebo in the nose and placebo in the arm. A placebo is just like the real vaccine but contains no active ingredients. Phase A: Participants will have 5 clinic visits over 56 days. They will receive a shot and a nasal spray at 2 of the visits, 28 days apart. At each visit, they will have a physical exam, with tests of their blood, urine, and nasal secretions. They will check their temperature at home and record any symptoms for 7 days after each vaccine. Phase B: Participants will stay in the hospital for at least 9 days. They will be infected with a flu virus. They will provide blood, urine, and nasal fluid samples. They will have tests of their heart function. They will remain in the hospital until they test negative for the flu 2 days in a row. They will have 2 follow-up visits, 4 and 8 weeks after leaving the hospital. ...