High prevalence of occult hepatitis B virus infection in children born to HBsAg-positive mothers despite prophylaxis with hepatitis B vaccination and HBIG

Absence of occult hepatitis B virus infection in sera of diabetic children and adolescents following hepatitis B vaccination

“…9 It was also reported in HB-vaccinated antiHBs-positive children born to HBsAg-positive mothers in China (3.2%) 10 and Iran (28%). 11 In the current study, OBI was not detected in IDDM children and adolescents, irrespective of antiHBs serostatus. These discrepancies in the incidence of OBI may reflect differences in endemicity of HBV, maternal HBV serostatus, and use of measures to prevent vertical transmission; technical variations in immunization use and efficacy; variations in adherence to immunization protocols; and different time points of evaluation.…”

HBsAg Variants: Common Escape Issues

“…Studies from our laboratory have revealed a high frequency of mutations at aa positions of the surface gene that coincides with the HLArestricted CTL epitope in patients with chronic hepatitis B, suggesting that these mutations might contribute to chronic infections (45). Nonetheless, accumulating evidence indicates that the genomic heterogeneity of the virus does not account for HBsAg negative status in all cases (25,39,46).…”

“…Furthermore, multiple mutations outside the surface protein could be found within the core, pre-S, X and polymerase with known functional and/or immune epitope reactivity (39,49,50).…”

“…A number of escape-variant viruses during the course of chronic infection within the "a" determinant were reported to be replicated in spite of the presence of antiHBs (15,39,(58)(59)(60)(61)(62)(63)(64)(65)(66)(67)(68). This phenomenon, which has been explored by molecular approaches in vaccinated individuals, may result from at least seven reasons.…”

“…Although the absolute number of new infections has been reduced in these regions, infections are most often observed in vaccinated infants born to HBV carrier mothers, suggesting that infants exposed to a maternal mutant virus may select for this strain during the development of vaccine-induced antibodies (39,89). An epidemiological model of the HBV that investigated possible patterns of emergence of a vaccine-resistant strain, showed that using pessimistic assumptions (i.e., the current vaccine provides no cross-immunity against the variant), the variant would not become dominant over the wild-type for at least 50 years (90).…”