Abstract
AIM: Hepatitis B surface antibody (HBsAb) plays an important role in the prevention of hepatitis B virus (HBV) infection, especially in immunocompromised individuals and in those infected with HBV.HBsAb levels often fluctuate and decrease.This study aimed to determine the regularity of HBsAb persistence among different populations. Moreover, the risk factors and the optimal cutoff value were determined to predict a decreasing population in HBsAb level. METHODS: The study involved 182 participants, including 76 patients with a 25% decrease in HBsAb levels and 106 patients with an HBsAb decrease rate of >50%. Both hepatitis B core antibody negative and positive patients were included.These patients were followed up for 10 years. The follow-up demographic and laboratory data were recorded and compared among the groups. Fluctuations in HBsAb data and HBsAb persistent immunity were evaluated. The independent factors and the optimal cutoff value were recorded. RESULTS: The first HBsAb median of Group 4 was lower than that of the other groups, and its median was 50.8 mlU/mL. In addition, the persistent immunity of the case groups was shorter than that of the control groups (p < 0.05). Furthermore, previous HBV history, use of antiviral drugs, and low levels of first HBsAb were independent risk factors in people with obviously decreased antibody levels. Also, when the optimum cutoff value on the receiver operating characteristic curve of the HBsAb difference value was taken as 8.53 mIU/mL, its sensitivity and specificity were 94% and 70% between the control and case groups, respectively. CONCLUSION: To maintain optimal immunity against HBV infection, patients with a previous HBV history, those taking antiviral drugs, and/or those with low levels of HBsAb should be reimmunized with the hepatitis B vaccine in a timely manner.