Persistence of immunologic memory in long-term hemodialysis patients and healthcare workers given hepatitis B vaccine: Role of a booster dose on antibody response

Hepatitis B (HB) vaccine is effective in producing protection against HB vi rus infection, but the persistence of immunity remains largely unknown. Sev enty-six hemodialysis (HD) patients (60: after primary HB vaccination and 1 6 with natural immunity) and 46 healthcare workers (32 after primary HB vac cination, and 14 with natural immunity) were followed up, for 10 years to, evaluate the persistence of immunity. Ten years after vaccination, the anal ysis showed a lower seroconversion rate (38 vs. 75%, p < 0.001) in HID pati ents as compared with healthcare workers. In the follow-up period, the prot ective immunity developed through, HB virus infection also showed a lower s eroconversion rate (44 vs. 86%, p < 0.025) in HD patients as compared with healthcare workers, To assess the status of immunologic memory, we administ ered a booster dose of HB vaccine 3-12 years (mean 6.7 +/- 0.6 years) after primary vaccination in a selected group of 37 HD patients who presented a decline of their antibodies or were nonresponders. In another group of 12 h ealthcare workers who had a decline of their antibodies, we also administer ed a, booster dose of HB vaccine 5-8 years (mean 5.8 +/- 0.3 years) after p rimary vaccination. Nineteen of the 37 HID patients (51%) presented an anam nestic response to the booster dose, and 15 of these (40%) were high respon ders. All of the healthcare workers responded to the booster dose with a hi gh antibody response. We conclude that patients undergoing HD not only have lower rates of immunization to HB than healthy adults, but also that these are frequently transient. Booster doses after a primary course of vaccine are effective in about the half of HD patients who presented a decline of t heir antibodies or were nonresponders but whether they are necessary is unc lear. The majority of healthcare workers continue to have high levels of pr otective HBs antibody for at least 10 years and routine boosters are not re quired. Copyright (C) 2001 S. Karger AG, Basel.