Assessing prevalence of HBV infection markers in older age groups and molecular genetic characterization of the identified HBV variants

Introduction. Despite successes in hepatitis B virus (HBV) molecular virology, prevention, and treatment, HBV infection remains relevant. The study aimed to analyze serological and molecular genetic markers among older individuals in Novosibirsk, and characterize identified HBV variants. Materials and methods. The study included 630 conditionally healthy individuals undergoing routine medical examination. Serological markers (HBsAg, AntiHBs, AntiHBc, HBeAg, AntiHBe) were determined by ELISA, and HBV DNA — by real-time PCR. Full-length genomic sequences of identified HBV isolates were obtained using next-generation sequencing (NGS). Results. HBV genetic material was detected in 6 patients, and their full genome sequences were obtained. The genotype and subgenotype of identified HBV variants were determined, and clinically significant mutations were analyzed. Only 29% of patients had protective antiHBs levels ( 10 IU/mL), with 38% also having antiHBc antibodies. Low-titer protective antibodies (10–100 IU/mL) were most common in both АntiНВs+/AntiНВс– and AntiНВs+/AntiНВс+ groups. Low titers were more frequent in the AntiНВs+/AntiНВс– group, while high titers ( 400 IU/mL) were more common in the AntiНВs+/AntiНВс+ group. Conclusions. It has been shown that among the older age groups, there is a low intensity of humoral immunity to HBV, which may indicate a widespread problem of reducing the level of protective antibodies over time post-vaccination, or insufficient vaccination coverage in this population group. A decrease in HBV antibody titer below the protective level in the elderly significantly increases the a of primary infection or reinfection with HBV in this population group. As a recommendation, the inclusion of AntiHBs serological monitoring in the medical examination program for the elderly can be considered. The data obtained also actualize the problem of booster vaccination in this age group. The total presence of mutations potentially associated with disease progression in the identified HBV variants and the widespread prevalence of mutations that can alter HBsAg antigenicity require attention to these patients.