Figure 1

TRANSGRIPE 1-2 trial design and procedures. Clinical trial visits are structured in five (or six) time points: initial screening baseline evaluation and administration of the first dose of vaccine in arms A and B (visit 1 and 2), administration in arm B of second dose of vaccine 5 weeks after inclusion (visit 3), short-term follow-up 10 weeks after inclusion (visit 4) and 15 weeks after inclusion (visit 5), as well as long-term follow-up 12 months after the first dose of vaccine (visit 6). Immunogenicity and drug safety were assessed at each programmed time point.