Serologic hepatitis B immunity in vaccinated health care workers.

BACKGROUND Hepatitis B vaccination is recommended for health care workers but has a nonresponse rate of 5% to 32% and an unknown duration of immunity. There is no standardized postvaccination protocol to confirm, monitor, and maintain immunity. OBJECTIVE To assess the hepatitis B serologic immune status in health care workers who were previously vaccinated. METHODS A convenience survey and an objective laboratory study, which included testing for hepatitis B surface antigen, core antibody, and qualitative and quantitative surface antibody (anti-HBs), were performed. The data collected included vaccination date, number of doses of vaccine, whether and when titers had previously been checked, titer results, sex of patient, job description, and age at the time of our study and at vaccination. RESULTS Group A (n = 109, 71%) had detectable anti-HBs titers, and group B (n = 45, 29%) had no detectable anti-HBs titers. Group A was vaccinated 4.80 +/- 0.30 (mean +/- SEM) years prior to our testing, received 2.91 +/- 0.04 (mean +/- SEM) vaccinations, and had a mean +/- SEM titer of 112.91 +/- 5.18 mIU/mL. There was no statistical significance in time since vaccination, number of doses of vaccine, sex, job description, age at the time of our serologic testing, or age at the time of vaccination between groups A and B. Six of 6 subjects given booster doses of vaccine in group B developed anti-HBs. Only 62 subjects (40%) in the entire study population had anti-HBs status previously determined, with 48 (77%) reporting immunity to hepatitis B virus. CONCLUSIONS Twenty-nine percent of the health care workers who were vaccinated against hepatitis B showed no serologic evidence of hepatitis B immunity. It is unclear whether these subjects are nonresponders, lost immunity, or retained anamnestic potential. Booster vaccination response in 6 of 6 subjects suggests immunity. We recommend (1) postvaccination testing within 1 to 2 months to document immunity, (2) periodic anti-HBs monitoring, and (3) booster vaccination to maintain protective titer levels.