[Immune response to hepatitis B vaccine and duration of protection in a dialysis unit].

Thirty members of the staff and fifty-one patients of Parma hemodialysis unit, serum negative for HBV markers, having completed the vaccination (HB-vax vaccine) against hepatitis B, were followed for two years after booster dose. After the third injection, the response to HB vaccine was significantly higher (p less than .0005) in staff members, than in patients. In the staff group, 83.3% were responders at mean titers of anti-HBs of 2703 mUI/ml; only 51% of patients developed anti-HBs at mean titres of 287 mUI/ml. As to either sex or age, no significant differences were observed in the two groups. Among hemodialysis patients the higher response (71.4%) was noted in the less than 40 aged individuals in comparison with those 40-60 (56.9%) or greater than 60 aged (38%). The persistence of the immunisation in both groups appeared to be statistically correlated to the anti-HBs titres after booster injection. At the end of the follow-up, 63.3% of the staff vaccinated members, but only 15.6% of the patients still had protective titre. No ill-effects induced by vaccine developed. Hepatitis B infection was only observed in one non responder member of the staff. The study demonstrates a low response to HB-vaccine and a rapid decrease of anti-HBs titre in the hemodialysis patients, thus leading to the need of frequent revaccination.