RESUMO
OBJECTIVE: The aim of the study was to evaluate, if elderly persons are sufficiently protected against infectious diseases by vaccination. PROBANDS AND METHODS: 300 elderly (> 60 years) and 300 young (< 35 years) persons from five Austrian cities were recruited according to the criteria of a field study. Antibody concentrations against tetanus, diphtheria, tickborne encephalitis and influenza were assessed by ELISA or by haemagglutination inhibition test. Disease and vaccination histories were recorded. RESULTS: The results of the study demonstrate that protection against infectious diseases was frequently insufficient in the elderly. This was partly due to the fact that old persons were not vaccinated according to recommended strategies. However, low antibody concentration and a short duration of protective humoral immunity were also observed in many elderly persons in spite of regular vaccination. This was not only the case in frail, but also in healthy elderlies. CONCLUSION: The data demonstrate that vaccination has a relatively weak and short-lasting effect in old age. The results of the study should stimulate discussions about strategies how vaccinations can be made more effective in old age. Improved campaigns, shortened vaccination intervals as well as the design of novel vaccines tailored to fulfill the specific demands of the aging immune system are imaginable.