Background: The success rate of anti-hepatitis B virus (HBV) immunization is known from the early 80s to be markedly lower in hemodialysis (HD) patients (around 60%) than in non-uremics (over 90%). It is also known to be inversely correlated with age in non-uremics, but the rate of successful immunization in the currently prevalent elderly HD patients is unknown.
Methods: We therefore reviewed our experience in patients vaccinated soon after starting HD in 1997-2000. A recombinant vaccine (Engerix 20 microg) was administered monthly in the deltoid muscle until anti-HBs titer was > or = 100 IU/l or up to 10 doses or death, whichever occurred first. Conventional serological tests for anti-HBc, anti-HBs and HBs Ag were performed 5, 6, 9 and 12 months after the first dose of vaccine.
Results: Ninety-six patients started HD during this period. Sixty-five of them were excluded for the following reasons: evidence of past HBV infection (n = 20, 21%), previous anti-HBV vaccination (n = 13, 14%), rapid transfer to another HD unit (n = 30, 31%), early death (n = 2, 2%). In the remaining 31 patients, with a median age of 73 (range 35-95) years, the vaccination schedule induced seroconversion in 13/31 (42%) and 16/23 (70%) after 5 and 12 months, respectively. The seroconversion rate after 12 months was 3/3 (100%), 9/12 (75%) and 4/8 (50%) in patients aged < 60 years, 60-75 years and > 75 years, respectively. Patients with seroconversion were younger (66 +/- 14 years) than those without seroconversion (76 +/- 9 years) (p = 0.048, unpaired t-test). In the whole cohort, evidence of past HBV infection was more common in patients originating from outside Northern Europe (mainly Africa or Mediterranean countries) (14/26, 54%) than in patients from Northern Europe (6/70, 9%) (p < 0.001, Fisher exact test).
Conclusion: Up to 50% of elderly (> 75 years) HD patients can be successfully immunized with a reinforced anti-HBV vaccination schedule, a proportion still much lower than in younger HD patients. The ultimate decision to vaccinate elderly HD patients more or less intensively, or not at all, should depend on the local epidemiology of HBV infection and the individual risk of acquiring HBV (e.g. through holiday dialysis in high prevalence countries). Before vaccinating, serological screening of patients originating from countries with high HBV prevalence is recommended.