Influenza A (H7N9) Vaccine Delivered Intradermally by High-density Microarray Patch (HD-MAP)

258 participants will be randomized to receive two doses (Day 1 and 22) of either VXS-1219, VXS-1219 with QS21 adjuvant (VXS-1219A), an intramuscular comparator (H7N9 vaccine or H7N9 + MF59® vaccine) or an uncoated, vaccine-free HD-MAP Delivery system (VXS-1219U). VXS-1219A is identical to VXS-1219 with the only difference being this investigational product will be formulated with QS21. VXS-1219U, the vaccine-free microarray patch delivery system comparator, includes a terminally sterilized polymer patch and does not include any vaccine coating formulation on the micro-projections, but is otherwise identical to VXS-1219 and VXS-1219A.

The primary objective of the study is to evaluate the safety and tolerability of two doses of H7N9 Influenza A vaccine (12 to 25 mcg HA) with and without QS21 adjuvant (3.3 to 8 mcg), administered by the microarray patch delivery system, compared to IM H7N9 vaccine (7.5 mcg HA) with and without MF59® and uncoated, vaccine-free microarray patch delivery system, administered 21 days apart.

The secondary objectives of the study are to evaluate the immune response to two doses H7N9 Influenza A vaccine (12 to 25 mcg HA) with and without QS21 adjuvant (3.3 to 8 mcg), administered by the microarray patch delivery system, compared to IM H7N9 vaccine (7.5 mcg HA) with and without MF59® and uncoated, vaccine-free microarray patch delivery system, administered 21 days apart.