Adjuvanting an inactivated influenza vaccine with conjugated R848 improves the level of antibody present at 6months in a nonhuman primate neonate model

Generation of a potent antibody response that can be sustained over time is highly challenging in young infants. Our previous studies using a nursery-reared nonhuman primate model identified R848 conjugated to inactivated influenza virus as a highly immunogenic vaccine for neonates. Here we determined the effectiveness of this vaccine in mother-reared infants as well as its ability to promote improved responses at 6 months compared to vaccination in the absence of R848. In agreement with our nursery study, R848 conjugated to influenza virus induced a higher antibody response in neonates compared to the non-adjuvanted vaccine. Further, the increase in the response relative to that induced by the non-adjuvanted vaccine was maintained at 6 months suggesting the increased antibody secreting cells that resulted from inclusion of conjugated R848 production were capable of surviving long term. There was no significant difference in quality of antibody (i.e. neutralization or affinity), suggesting the beneficial effect of conjugated R848 during vaccination of neonates with inactivated influenza virus is likely manifest during the early generation of antibody secreting cells.