Molecular and serological detection of occult hepatitis B virus among healthy hepatitis B surface antigen-negative blood donors in Malaysia

Low Risk of Occult Hepatitis B Infection among Vietnamese Blood Donors

Occult hepatitis B infection (OBI) is characterized by the presence of low levels of hepatitis B virus (HBV) DNA and undetectable HBsAg in the blood. The prevalence of OBI in blood donors in Asia ranges from 0.013% (China) to 10.9% (Laos), with no data available from Vietnam so far. We aimed to investigate the prevalence of OBI among Vietnamese blood donors. A total of 623 (114 women and 509 men) HBsAg-negative blood donors were screened for anti-HBc and anti-HBs by ELISA assays. In addition, DNA from sera was isolated and nested PCR was performed for the HBV surface gene (S); a fragment of the S gene was then sequenced in positive samples. The results revealed that 39% (n = 242) of blood donors were positive for anti-HBc, and 70% (n = 434) were positive for anti-HBs, with 36% (n = 223) being positive for both anti-HBc and anti-HBs. In addition, 3% of blood donors (n = 19) were positive for anti-HBc only, and 34% (n = 211) had only anti-HBs as serological marker. A total of 27% (n = 170) were seronegative for any marker. Two of the blood donors (0.3%) were OBI-positive and sequencing revealed that HBV sequences belonged to HBV genotype B, which is the predominant genotype in Vietnam.

Estimates of the prevalence of occult HBV infection in Asia: a systematic review and meta-analysis

PURPOSE

Occult Hepatitis B virus infection (OBI) is of great significance to the transmission of Hepatitis B virus (HBV) and the evolution of the patient's clinical outcome. We conducted a systematic review and meta-analysis to estimate the prevalence of OBI in Asia.

METHODS

Literature search was conducted in PubMed, Cochrane Library database, Web of Science and Embase with the keywords of 'Hepatitis B virus', 'occult infection', 'prevalence'. 70 studies were included in the meta-analysis. Meta-analysis was performed using random-effects models to calculate the pooled prevalence of OBI and 95% confidence interval (CI). The data were analyzed in R 4.1.2.

RESULTS

The overall prevalence of OBI was 4% (95%CI: 0.03-0.06) in Asia. Subgroup analysis based on geographic region showed a prevalence of 3% (95%CI 0.02-0.06) in East Asia, 9% (95%CI 0.05-0.15) in West Asia, 3% (95%CI 0.01-0.11) in Southern Asia and 9% (95%CI 0.05-0.15) in Southeast Asia. Subgroup analysis demonstrated a prevalence of 1% (95%CI 0.00-0.02) in general population, 5% (95%CI: 0.03-0.08) in high-risk population, 9% (95%CI: 0.03-0.22) in the human immunodeficiency virus (HIV)-infected patient, 18% (95%CI: 0.09-0.32) in the hepatopathy patients.

CONCLUSION

Based on the meta-analysis of the prevalence of OBI in different populations, we concluded that the prevalence of OBI in the high-risk population, hepatopathy patients, and HIV-infected patients was higher than that in the general population. A systematic review showed that OBI was associated with disease progression and prognosis. Therefore, these populations should be routinely screened for OBI and promptly intervened to avoid promoting disease progression.

Molecular characteristics of the full-length genome of occult hepatitis B virus from blood donors in China

The characteristics of a large sample size of the full-length genome of occult hepatitis B virus (HBV) infection (OBI) have not been extensively explored in China. Voluntary blood donors who were HBsAg-negative/HBV NAT-positive (HBsAg−/HBV NAT+) were identified by blood screening and recruited. Blood samples were tested for HBV serologic markers, viral loads, and PCR to identify OBI. HBV full-length genomes were obtained by amplifying two fragments using nested PCR. The characterization of OBI strains was based on sequence analyses compared with HBsAg+ strains obtained from the same donor population. Of the 50 full-length genomes of 172 identified OBI strains, 33 were classified as genotype B (OBI_B) and 17 strains as genotype C (OBI_C). Significantly higher nucleotide variabilities were observed in the Pre-S2/S promoter region (SP2) and core upstream regulatory sequence (CURS) in OBI_B than in their HBsAg+ controls (P < 0.05). Both OBI_B and OBI_C showed higher amino acid (aa) variabilities in Pol and Pre-S/S regions than their controls (P < 0.05). In addition, 19 novel OBI-related mutations were found spanning the four open reading frames (ORFs) of the HBV genome. Four novel deletions and one novel insertion were also found in OBI_C strains. Several novel OBI-related mutations spanning the four ORFs of the virus were identified by characterizing a large sample size of the full-length OBI genome, which may affect the production of HBsAg and contribute to the occult infection of HBV.

Occult Hepatitis B virus (HBV) infection and challenges for hepatitis elimination: A literature review

Occult hepatitis B infection (OBI) is characterized by the detection of hepatitis B virus (HBV) DNA in serum or liver but negativity for hepatitis B surface antigen. OBI, which is thought to be maintained by host, immunological, viral and/or epigenetic factors, is one of the most challenging clinical features in the study of viral hepatitis. Currently, there is no validated detection test for OBI. It is believed that OBI is widely distributed throughout the world, with a higher prevalence in populations at high-risk HBV, but the detailed worldwide prevalence patterns are unknown. We conducted a survey of recently published studies on OBI rates across all continents. High prevalence rates of OBI are observed in some specific groups, including patients with hepatitis C virus, human immunodeficiency virus co-infection or hepatocellular carcinoma. In 2016, the World Health Organization adopted strategies to eliminate viral hepatitis by 2030, but the difficulties in detecting and treating OBI currently challenge this goal. Subjects with OBI can transmit HBV, and episodes of reactivation can occur. Further studies to understanding the mechanisms that drive the development of OBI are needed and can contribute to efforts at eliminating viral hepatitis.

Evaluation of a hepatitis B virus protection intervention among interns at Zagazig University Hospitals, Egypt

BACKGROUND

Hepatitis B virus (HBV) infection is the most common serious liver infection. The study aimed to evaluate the effect of a HBV protection intervention on interns, as regards their knowledge, attitude and immune response to HB vaccine and to identify the factors affecting their compliance and immune response to HB vaccination at Zagazig University Hospitals.

METHODS

A quasi-experimental study was conducted in 3 phases over 10 months. Phase 1: assessment of knowledge, attitude and HCV/HBV immune status. Phase 2: the implementation of HBV protection campaign; vaccine administration and health education sessions. Phase 3: the assessment of the immune response to the vaccine and the change in knowledge and attitude.

RESULTS

Out of 120 participants, 60% were compliant to the vaccination schedule. Needle-stick injury, the seriousness of HBV infection and attendance of infection control courses are the motivating factors to vaccination (p < 0.05). After the 3rd dose, 9.7% were non-responders. BMI and diabetes were the statistically significant predictors of the immune response. The HCWs compliant with vaccination schedule had higher mean scores regarding; total knowledge (15.5 ± 2.1), p < 0.0001 and attitude (14.34 ± 3.8) p < 0.05. A significant improvement is recorded from the posttest results, p < 0.000.

CONCLUSIONS

A comprehensive protective program against HBV is an effective tool. A compulsory vaccination program is still needed for interns. Post vaccination monitoring program, including protective measures for vaccine non responders is urgently needed with strict follow up of at risk groups. Occult HBV cases should not be overlooked when screening for immune response to vaccine.

Risk factors of hepatitis B virus surface antigen carriage and serological profile of HBsAg carriers in Lomé Togo, 2016

BACKGROUND

In Togo, the prevalence of Hepatitis B Virus Surface Antigen (HBsAg) among young people aged 15-24 years was estimated at 16.4% in 2010; however, risk factors for HBsAg carriage are poorly documented. We sought to identify risk factors for HBsAg carriage and the serological profile of HBsAg carriers in Lomé (capital city of Togo).

METHOD

We conducted a case control study from October 2016 to March 2017 in Lomé. Cases and controls were randomly selected from a database of Institut National d'Hygiène (INH) of Lomé during a free screening campaign for hepatitis B. We calculated means, frequencies, proportions, odds ratios (OR), and 95% confidence interval (CI) and performed logistic regression.

RESULTS

We included 83 confirmed cases and 249 controls. The median age was 31 years among cases and 30 years among the controls. The sex ratios (M/F) were 11/6 among cases and 4/3 for the controls. The independent risk factors for HBsAg carriage were the awareness of hepatitis B serological status (OR = 3.56, 95% CI [1.80-7.04]) and Kabyè-tem ethnic group (OR = 3.56, 95% CI [1.98-6.39]). Among HBsAg carriers, 13.3% were at the viral replication stage (all of whom were between 30 and 45 years of age) and 1.2% were at the acute stage of the disease. The prevalence of co-infection with hepatitis B and C was 4.80%. All co-infections were in women aged 24-28 years.

CONCLUSION

The Kabyè-tem ethnic group is at risk of HBsAg carriage in Lomé. Of note, most HBsAg carriers in this ethnic group are aware of their HBsAg serological status. Furthermore, the prevalence of Hepatitis among adults of reproductive age is high and is cause for concern. We therefore recommend screening and vaccination campaigns at subsidized prices among people aged 30 years and older.

Infections interplay with non-communicable diseases

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