Fig. 2. Vaccine study design.

a Safety and efficacy vaccine study design follows previously reported design^18,29. Briefly, 7-weeks old DBA/2J mice, ½ female were primed and boosted, 3 weeks apart with one of the recombinant FLUBV vaccines. At 3 weeks post-boost, mice were challenged with an aggressive dose of the B/Bris PB2 F406Y strain. Mice were monitored for clinical signs and survival after prime, boost and challenge as indicated. b Body weight changes and c survival post-prime virus inoculation of female (left panels) and male (right panels) mice. Yellow symbols correspond to groups of mice inoculated with IGIP-containing FLUBV recombinants. Gray symbols correspond to mice inoculated with non-IGIP FLUBV recombinants whereas red symbols correspond to mice inoculated with the FLUBV wt strain (as previously reported^18,29). Number of mice that succumbed to virus inoculation are denoted with the “†” symbol with colors matching the corresponding group.