Response of health care workers with isolated antibody to hepatitis B core antigen to hepatitis B vaccine.

Isolated hepatitis B core antibody (antiHBc) without hepatitis B surface antigen (HBsAg) or hepatitis B surface antibody (antiHBs) is found during routine screening for hepatitis B virus (HBV) markers. Isolated antiHBc may indicate immunity against HBV or occult infection. To determine the immune response of health care workers (HCWs) with isolated antiHBc, HCWs were divided into two groups. A single dose of recombinant hepatitis B (HB) vaccine was administered to HCWs with isolated antiHBc (n = 36) and healthy HCWs (n = 20) seronegative for HBsAg, antiHBc and antiHBs. One month later, the subjects were tested for antiHBs. Twenty-one of 36 HCW (58.3%) in the antiHBc group had antiHBs, while only 1 of 20 HCW (5.0%) in the seronegative control group had a detectable antiHBs titer exceeding 10 mIU/ml. The antiHBs response in HCWs with antiHBc was significantly higher than in the seronegative group. The subjects' sera were tested for HBV DNA by nested PCR. Of those with antiHBc, 4 had detectable HBV DNA (occult HBV infection). None of these 4 responded to the vaccine. Therefore, the response elicited by a single dose of HB vaccine administered to patients with antiHBc may serve as an indicator of occult HBV infection.

Seroprevalence and risk factors of hepatitis B virus infection among health care workers at the Institute of Neurology.

OBJECTIVES: To define the seroepidemiology of Hepatitis B virus (HBV) infection among health care workers (HCWs) in the Institute of Neurology, and to evaluate the risk factors of HBV markers. MATERIAL AND METHOD: Blood samples were taken from 548 HCWs for HBV profiling (HBsAg, anti-HBs and anti-HBc) by Microparticle Enzyme Immunoassay (MEIA) methods. Questionnaires of demographics, type, and duration of work, history of blood exposure, HBV vaccination, and non-occupational risks of HBV infection were interviewed. RESULTS: Twenty-nine (5.3%) HCWs were HBsAg positive, 135 (24.6%) had anti-HBc with anti-HBs suggesting immunity acquired from a previous HBV infection, 232 (42.3%) had totally negative profiles, 40 (7.3%) had anti-HBc only, 105 (19.2%) had protective levels of anti-HBs, 7 (1.3%) had low anti-HBs levels. The significant risk factors included not having received the hepatitis B vaccine, male gender, past history of jaundice, viral hepatitis, family history of hepatoma, spouse with hepatitis B, and duration of employment in a clinical environment exceeding 5 years. No significant differences were found among HCWs regarding frequency of exposure to blood products. CONCLUSION: Base on the significant risk factors of hepatitis B virus infection among HCWs, these findings will help implement effective measures aimed at preventing HBV infection.