The study will be conducted as a Phase I prospective, randomized study in healthy adult subjects at a single center. Adult subjects age 18 to 47 years and meeting all enrollment criteria will choose to participate as subjects who receive unadjuvanted or adjuvanted H7H9 pIIV vaccine followed by a live vaccine boost at 4 weeks (Group 1, n=24), 12 weeks (Group 2, n=24), or 24 weeks (Group 3, n=24), or to be in an observational group (Group 4, n=16) which will not be scheduled for a booster dose but may serve as a roll-over group for subjects who withdraw prior to the second vaccination but agree to remain in follow-up. Within each group, subjects will be randomized at a 1:1 ratio to receive a single dose of either unadjuvanted H7N9 pIIV at 15 mcg (Subgroup A), or the same vaccine adjuvanted with the oil-in-water emulsion, MF59, (Subgroup B) delivered intramuscularly. Finally, a fifth group (Group 5, n=12) will receive two intramuscular doses of adjuvanted H7N9 pIIV separated by four weeks. The total duration of study participation for all subjects will be approximately 13 months. Recruitment, enrollment and administration of study product will be suspended when one of the following occurs in the clinical or research laboratory at the clinical site: at least two respiratory cultures or PCR assays are determined to be positive for influenza or at least 10% diagnostic tests (rapid tests, respiratory cultures or PCR assays) performed for influenza as positive during two consecutive weeks in the clinical or research laboratory at the clinical site. Recruitment, enrollment and administration of study product may be resumed after 2 weeks without a signal that influenza is still circulating in the community, as defined by the same measures that indicate the start of influenza season (i.e., less than 2 respiratory cultures or PCR assays are determined to positive for influenza or less than 10% of diagnostic tests performed or influenza with positive results). The primary objectives of this study are to (1) assess the safety of H7N9 pLAIV administered to individuals who have previously received MF59-adjuvanted or unadjuvanted H7N9 pIIV, (2) evaluate the ability of a single dose of unadjuvanted H7N9 pIIV to prime for enhanced immunogenicity (booster response) to subsequent administration of antigenically-matched H7N9 pLAIV vaccine, and to (3) evaluate the ability of a single dose of MF59-adjuvanted H7N9 pIIV to prime for enhanced immunogenicity (booster response) to subsequent administration of antigenically-matched H7N9 pLAIV vaccine. The secondary objectives of this study are to (1) assess the safety of priming with MF59-adjuvanted H7N9 pIIV or unadjuvanted H7N9 pIIV, (2) assess the immune response in subjects vaccinated with a single dose of MF59-adjuvanted H7N9 pIIV or a single dose of unadjuvanted H7N9 pIIV, and to (3) compare the booster effect seen after intervals of 4 weeks, 12 weeks, or 24 weeks within each priming group.
A phase I prospective, randomized study in healthy adult subjects at a single center. Adult subjects age 18 to 47 years and meeting all enrollment criteria will choose to participate as subjects who receive inactivated vaccine followed by a live vaccine boost at 4 weeks (Group 1), 12 weeks (Group 2), or 24 weeks (Group 3), or to be in an observational group (Group 4) which will not be scheduled for a booster dose but may serve as a roll-over group for subjects who withdraw prior to the second vaccination but agree to remain in follow-up. A fifth group will receive two intramuscular doses of adjuvanted H7N9 pIIV separated by four weeks. The primary objectives of this study are to (1) assess the safety of H7N9 pLAIV administered to individuals who have previously received MF59-adjuvanted or unadjuvanted H7N9 pIIV, (2) evaluate the ability of a single dose of unadjuvanted H7N9 pIIV to prime for enhanced immunogenicity (booster response) to subsequent administration of antigenically-matched H7N9 pLAIV vaccine, and to (3) evaluate the ability of a single dose of MF59-adjuvanted H7N9 pIIV to prime for enhanced immunogenicity (booster response) to subsequent administration of antigenically-matched H7N9 pLAIV vaccine.