THE BOOSTER EFFECT IN ELDERLY PATIENTS LI VING IN GERIATRIC INSTITUTIONS

BACKGROUND: Tuberculinic response is weaker in elderly patients. To kn ow the real tuberculinic reactivity in elderly patients living in geri atric institutions in Catalonia, Spain, and to reduce the probability of false negatives this study was carried out to detect the booster ef fect. METHODS: Three hundred forty three individuals with a mean age o f 81 +/- 6.5 years, residing in four geriatric centers within the Cent ral Health Care Region of Catalonia, were studied. After performing th e first Mantoux intradermoreaction this was repeated at one week in ca se of negativity. A third test was carried out after one more week on persistence of negativity. Qualitative study was carried out on cell i mmunity in those patients whose first Mantoux test was negative. RESUL TS: The first Mantoux test was positive in 163 patients (47.5%) and th e performance of the second and third test in cases of negativity of t he previous test increased the number of positivities by 12.5% and 4.1 %, respectively, up to a total of 220 patients (64%). In the patients who did not react to the first intradermoreaction and who preserved ce ll immunity a booster effect was obtained in 57 (52.8%). The prevalenc e of tuberculous infection in this group of elderly patients calculate d in the group with preserved cell immunity was 81.2% while the morbid ity of tuberculous disease in the positive cases in the Mantoux test w as 1.8%. CONCLUSIONS: Given the high frequency of the booster effect i n elderly people, systematic testing is recommended to Investigate tub erculinic reactivity in patients who are initially negative on Mantoux intradermoreaction.