BackgroundPresence of occult hepatitis B infection (OBI) renders HBs antigen (HBsAg) undetectable by ELISA. Therefore it is valuable to evaluate the frequency of OBI among healthy blood donors to improve and perhaps change the strategies of blood screening to reduce the risk of HBV transmission.ObjectivesThe aim of this study was to determine the presence of HBcAb and HBV DNA among Iranian HBsAg negative healthy blood donors who donated their blood to the Tehran Blood Transfusion Center during 2011.Patients and Methods1000 serum specimens negative for HBsAg, HCV antibody and HIV antibody were collected from healthy blood donors and tested for HBcAb. Presence of hepatitis B viral DNA was checked in HBcAb positive samples by nested PCR with two sets of primers to amplify part of HBV S gene.ResultsThere were 64 women and 936 men in the population under study. The mean ± SD age of the donors was 38 ± 11 years. 80 out of 1000 samples (8%) were found to be positive for HBcAb. HBV DNA was detected in 50% of HBcAb positive specimens. The mean ± SD age of donors without HBV DNA was 37.7 ± 10.5 years and for donors with HBV DNA was 40.9 ± 11.2 years (P = 0.05).ConclusionsOBI was prevalent among 50% of HBcAb positive healthy blood donors. The frequency of positive HBcAb among healthy HBsAg negative blood donors was comparable to previous studies reported from Iran. On the other hand, the frequency of HBV DNA in HBsAg negative blood donors was higher than previous reports.

Background: A higher prevalence of hepatitis B virus (HBV) infection has been reported in persons with intellectual disability as well as the nurses working in closed institutions compared to the general population. Objectives: In the present study, the serological and molecular markers of HBV infection in individuals with intellectual disability of closed institutions were investigated. Methods: Blood samples were derived from 400 persons with intellectual disability living in six institutions in Tehran and tested for HBsAg and HBcAb. Nested PCR, direct sequencing, and phylogenetic analysis were performed to determine the HBV genotypes and mutational patterns of HBsAg. Also, HBsAb was tested for HBV DNA positive cases. Results: Twenty-eight (7.0%) patients were positive for the HBsAg serological test. Furthermore, six HBV occult cases were identified. In total, out of 41 patients with HBV infection markers, 26 cases were positive for HBV DNA. Of these patients, 15 full-length HBsAg were successfully amplified and sequenced. All strains belonged to genotype D and subtypes ayw2 and ayw3. These 15 isolated strains carried several immune escape mutants in the S genes. Surprisingly, mutations related to antiviral resistance were detected in the overlapped pol genes of strains isolated from naïve-treatment patients. Conclusions: The observed frequency of HBV infection in individuals with intellectual disability was higher than the reported estimation of HBV infection in Iranian blood donors and the general population. All HBV isolates from these patients represented a homogenous genotype and corresponded with other reported strains from Mediterranean countries. The high frequency of immune escape strains, despite vaccination and detection of identical mutational patterns in different genes, might indicate that persons with intellectual disability have shared vaccine-escape and drug-resistant HBV strains.