tNIV trivalent nanoparticle influenza vaccine VE vestigial esterase VL variable light WHO World Health Organization WT wild-type References Xu, X.; Blanton, L.; Elal, A.I.A.; Alabi, N.; Barnes, J.; Biggerstaff, M.; Brammer, L.; Budd, A.P.; Burns, E.; Cummings, C.N.; et al...