H7N9 viruses caused an outbreak of severe respiratory disease in China in 2013-2014, which was associated with severe respiratory illness, acute respiratory distress syndrome (ARDS), intensive care unit (ICU) admissions, and death. The outbreak affected older adults and highlighted the need for a vaccine that is effective in this population. Prior studies have demonstrated the safety and immunogenicity of a vaccination regimen in which administration of the experimental H7N9 vaccine (H7N9 Anhui 2013/AA ca) was followed by an H7N9 inactivated vaccine in younger adults. This study will evaluate the safety and immunogenicity of a similar vaccination regimen in healthy adults, 50 to 70 years old, who are H7N9 seronegative.~Participants will be admitted to the inpatient unit 2 days before they will receive their first vaccination with the H7N9 Anhui 2013/AA ca vaccine. All participants will receive one dose of the H7N9 vaccine, delivered as a nasal spray, on Day 0. While in the inpatient unit, study procedures will include physical examinations, medical history reviews, nasal swabs, and blood and urine collections. On Day 9, participants will be discharged from the inpatient unit provided they meet certain medical criteria. If not, they will remain in the isolation unit until the criteria are met.~On Day 26, participants will be readmitted to the inpatient unit, and on Day 28, they will receive one dose of the H7N9 vaccine delivered as a nasal spray. Participants will remain in the inpatient unit until Day 37 and will take part in all of the same study procedures that occurred during the first inpatient stay. On Day 56, all participants will attend a study visit for a blood collection and nasal swab. On Day 98, all participants will receive one dose of the inactivated subvirion H7N9 vaccine. They will attend study visits on Days 101, 105, 112, 126, 154, and 180, which will include the same study procedures that occurred during the inpatient visits.
H7N9 viruses have caused an outbreak of severe respiratory disease in 2013-2014 in China that affected many older adults. This study will evaluate the safety of and immune response to a live attenuated H7N9 vaccine in adults 50 to 70 years old.