RESUMO
BACKGROUND: Recent retrospective studies demonstrate that elderly persons have a shortened protection period following vaccination with recall antigens. METHODS: We now analysed the effect of booster vaccination with a multivalent vaccine containing tetanus, dipththeria, pertussis and polio antigens in 252 healthy elderly persons. The magnitude of the humoral immune response was assessed by antibody measurements. RESULTS: Comparison with a small control group of 21 younger persons demonstrates that pre- and post-vaccination antibody concentrations are lower in elderly persons for all antigens except polio, for which higher pre- and similar post-vaccination antibody levels are observed. Using multiple linear regression analysis we also show that the magnitude of the humoral immune response in elderly persons greatly depends on pre-vaccination antibody concentrations in the case of tetanus, diphtheria and pertussis, but much less so in the case of polio, against which priming and preceding booster immunizations were performed with attenuated live vaccine. CONCLUSION: Regular booster vaccinations throughout life are of clinical importance to maintain the ability to respond to recall antigens in old age. Longer lasting protection and good responsiveness to boosting in spite of low antibody titres can be expected following exposure to live vaccine earlier in life.
