Improvement in the immune response to inﬂuenza virus vaccination in the elderly represents the primary unmet need in inﬂuenza virus vaccination. We have shown that topical application of immunostimulating (IS) patches containing heat-labile enterotoxin of Escherichia coli (LT) enhances immune responses to injected vaccines. We extend these ﬁndings and show that LT-IS patch application enhances the antibody responses to inﬂuenza virus vaccination in both young and aged mice. LT-IS patches markedly increased inﬂuenza virusspeciﬁc immunoglobulin G (IgG), hemagglutination inhibition antibody, mucosal antibody, and T-cell responses. The magnitude of the immune responses in aged mice receiving an LT-IS patch was equivalent to or greater than that of the immune responses in young mice given vaccine alone. These results suggest that addition of an LT-IS patch may compensate for the deﬁcient immune function seen in the aged in response to inﬂuenza virus vaccination. Therefore, use of an LT-IS patch could be a new, safe, and simple immunization strategy that may signiﬁcantly improve the outcome of inﬂuenza virus vaccination in the elderly.