An influenza vaccine adjuvanted with a sub-micron oil-in-water emulsion elicits significantly higher immune responses in human pediatric populations. Compared to an existing unadjuvanted pediatric influenza vaccine, the adjuvanted vaccines provided herein can induce in children a longer persistence of high serum antibody titers and also longer seroconversion and seroprotection. The improvement in immune responses is seen for both influenza A virus and influenza B virus strains, but it is particularly marked for influenza B virus. Moreover, while the existing vaccine provides poor immunity in children after a single dose, the adjuvanted vaccine provides high seroprotection rates against the influenza A virus H3N2 subtype even after a single dose. Furthermore, the adjuvanted vaccine offers significantly better seroprotection against mismatched strains of influenza A virus.
