This study will assess priming with antigenically mismatched live attenuated A/H7N3 influenza virus vaccine (H7N3 pLAIV) followed by inactivated A/H7N9 influenza virus vaccine (H7N9 pIIV) in healthy adults.~Participants will receive a dose of H7N3 pLAIV on Days 0 and 28, followed by a single dose of H7N9 pIIV on Day 84.~On Days -2 and 26, participants will be admitted to an inpatient clinic. They will receive the H7N3 pLAIV vaccine on Days 0 and 28. They will remain in the clinic for 9 days after receiving the vaccine and until they are no longer shedding vaccine virus. An additional study visit will occur on Day 56.~On Day 84, participants will receive the H7N9 pIIV vaccine. Additional study visits will occur on Days 87, 91, 98, 112, 140, and 180. Study visits may include physical examinations, nasal washes, and blood and urine collection. Participants will be contacted by phone on Day 264 for follow-up health monitoring.
The purpose of this study is to assess priming with antigenically mismatched live attenuated A/H7N3 influenza virus vaccine followed by inactivated A/H7N9 influenza virus vaccine in healthy adults.