The public health importance of the effects of aging on
influenza vaccine responses has become increasingly more evident
as the global elderly population continues to dramatically rise.
Development of effective influenza vaccines targeted
specifically to this high-risk group remains a high priority.
The protection elicited by a successful influenza vaccine for
the elderly will likely need both humoral and cellular-mediated
immunity, requiring full engagement of the host immune system.
However, during aging the coordination and regulation of
immunological functions are impaired as a result of
immunesenescence [30 In this study, we identified significant
differences in the immune response to an inactivated subunit
influenza vaccine between seniors and young adults. We also
determined the extent to which a four-fold higher dosage vaccine
might enhance the immune response despite these age-related
immunological defects. Our results showed that there was a clear
age-related impairment in the HAI and VN antibody re