HOW TO MANAGE THE IMMUNIZATIONS OF THE OL DER TRAVELER

Along with the growth of travels, the ageing of the population multipl ies the number of older travellers. 13 % of travellers could be at lea st 65 years old. It is admitted that there is no upper age limit to pe rform immunizations. Immunizations are all the more useful for older p eople because age generally aggravates infectious diseases. With age t he immune response decreases definitely, especially that depending on cellular immunity as well as the humoral response, as it has been obse rved with vaccinations against tetanus, flu pneumococcal infections an d hepatitis B. The first series of immunizations could be more affecte d by age than boosters. But a lot of questions still remain unanswered . Is there a maximum age beyond which the immune response would be una dapted to such an extent that it would be necessary to modify the immu nization protocols as well as the periodicity of boosters? 75 years ? 80 years ? is this age the same for all individuals ? Is that a matter of a lower level of the antibody response, or rather of a slower dela yed response? The planning of older travellers immunizations meets ano ther difficulty. their often vague knowledge of past immunization reco rds and infectious diseases. One is often reduced to conjectures. Thus men, who have served in the army since the beginning of World War ii are supposed to have got the first series of immunization against teta nus and diphtheria, but how can we restore their immunity (once we hav e defined the maximum age) when boosters have been either insufficient or missing ? Conversely for women born before 1945, who were probably never immunized, a first series of immunization is warranted. On the other hand, since the immunization against poliomyelitis only came int o effect in the sixties, most older adults have never been immunized b ut have acquired in the past a natural immunity from their contact wit h wild polio viruses. Naturally acquired antipoliovirus immunity doesn 't seem to have decreased with age, unlike antidiphtheria and antiteta nus immunity, as shown by recent serologic studies. Thus would a singl e booster with inactivated polio vaccine be sufficient to reinforce th e immunity of most older travellers who have never been immunized ? Co nsidering these uncertainties, one could think of carrying out a serol ogic assessment prior to establishing an immunization program, as it h as already been recommended for the immunization against hepatitis A. What would its feasibility be ? There are quite a lot of questions to discuss. May this round table help define these questions and specify which investigations would be necessary to solve them, as well as prog ram more rationally the immunizations of the older traveller.