ANTIBODY-RESPONSE TO WHOLE-VIRUS AND SPLIT-VIRUS INFLUENZA VACCINES IN SUCCESSFUL AGING

The antibody response to influenza vaccination has been variably repor ted to be decreased in elderly individuals. To determine the effect of ageing alone on this antibody response, a group of carefully-screened healthy elderly subjects were compared with young adult controls. Ant ibody titres for several strains of influenza were measured before and after vaccination with whole-virus (WVV) and split-virus influenza va ccines (SVV) in two successive years. In general, the antibody respons e to WVV was greater than the response to SVV. Both groups showed a si milar response to the H3N2 strain but the elderly group showed a lower response to the H1N1 and B strains of virus contained in the vaccine. Antibodies to older strains of influenza A but not B were stimulated by vaccination with SVV. In the elderly group, the response to older v iral strains was relatively increased compared with newer strains. In contrast, the young control group had better antibody responses to the newer than to the older strains of influenza tested. Reductions in th e antibody response to influenza vaccination may, therefore, be relate d to the phenomenon of original antigenic sin and the cohort effect of exposure to H1N1 during childhood in the elderly group studied. The i ncreased immunogenicity of WVV must be considered in light of the curr ent wide use of SVV in the elderly.