Genotypic distribution of hepatitis B virus (HBV) among acute cases of HBV infection, selected United States counties, 1999-2005

Insights on 21 Years of HBV Surveillance in Blood Donors in France

Hepatitis B virus (HBV) infection is the most frequent viral infection found in blood donors (BDs) in France. We analyzed the epidemiological and sero-molecular data on HBV infection gathered over the past two decades by the French haemovigilance surveillance network, blood screening laboratories, and the national reference center for transfusion infectious risks (NRC). Between 2000 and 2020, 6149 of the 58,160,984 donations (1.06/10,000) tested HBV positive, 98% of them from first-time blood donors (FTBDs). In addition, 2212 (0.0071%) of the 30,977,753 donations screened for HBV DNA tested DNA positive, of which 25 (1.1%) were positive only for this marker. HBV prevalence decreased by 2.8-fold and the residual risk for transfusion-transmitted HBV infection decreased 13-fold and was divided by 13. The major risk factor for HBV infection was the origin of donors (endemic country, 66.5%), followed by parenteral exposure (10.7%). In the whole HBV-positive BD population, genotype D was predominant (41.8%), followed by genotypes A (26.2%) and E (20.4%), reflecting the geographical origin of donors. The low and decreasing prevalence and incidence of HBV infection in French BDs, coupled with a screening strategy using three HBV markers (HBsAg, anti-HBc and DNA), ensures a high level of blood safety, further reinforced by the implementation of pathogen-reduction measures.

Hepatitis B Virus Genotype G: The Odd Cousin of the Family

With a widespread distribution but low prevalence worldwide, the hepatitis B virus (HBV) genotype G (HBV/G) is a recently described genotype for which the origin and biology are poorly understood. Some unique features make HBV/G the most peculiar of all genotypes. In this review, we reflect on the major milestones in HBV/G research, highlighting the main aspects of its discovery, molecular epidemiology, and virological and clinical characteristics. We also illustrate common pitfalls in the routine detection, which may lead to underestimated rates of HBV/G infection. Large-scale analysis of data from dozens of articles was further performed, with the aim of gaining comprehensive insights into the epidemiological aspects of HBV/G. Finally, we point out recent findings on HBV/G origins and discuss new perspectives regarding the evolutionary history of HBV/G and the plausibility of an African geographic re-emergence of this genotype.

Molecular epidemiology of HBV among HIV infected individuals in Chennai, south India

Hepatitis B is a major co-infection among people with HIV (PWHIV) worldwide. There is a paucity of data on HBV genetic diversity in India, which would be useful for targeted preventive and management interventions. To characterize the distribution of HBV genotypes and sub-genotypes, samples of 180 HIV-HBV co-infected individuals from a study previously conducted to estimate the prevalence of HBV co-infection were analyzed. Nested PCR using type-specific primers was used to identify the various HBV genotypes. Partial HBV S sequences were generated for a subset of samples using Sanger sequencing. Mutation analysis was done using the online HBVseq program. PCR based genotyping documented D (69.4 %) and A (5.6 %) to be the major genotypes in the study population. Infection with multiple genotypes was observed in 25 % co-infected individuals. D2, D5, A2, and A1 were the sub-genotypes detected. Mutations 184K and 173L were identified. HBV genotypes/ sub-genotypes play a pivotal role in the clinical outcome of chronic hepatitis B (CHB). Therefore, monitoring of CHB cases is needed to track disease progression, including early detection of hepatocellular carcinoma.

Genome-wide association study identifies new loci associated with risk of HBV infection and disease progression

BACKGROUND

Recent studies have identified susceptibility genes of HBV clearance, chronic hepatitis B, liver cirrhosis, hepatocellular carcinoma, and showed the host genetic factors play an important role in these HBV-related outcomes.

METHODS

Collected samples from different outcomes of HBV infection and performed genotyping by Affymetrix 500 k SNP Array. GCTA tool, PLINK, and Bonferroni method were applied for analysis of genotyping and disease progression. ANOVA was used to evaluate the significance of the association between biomarkers and genotypes in healthy controls. PoMo, FST, Vcftools and Rehh package were used for building the racial tree and population analysis. FST statistics accesses 0.15 was used as a threshold to detect the signature of selection.

RESULTS

There are 1031 participants passed quality control from 1104 participants, including 275 HBV clearance, 92 asymptomatic persistence infection (ASPI), 93 chronic hepatitis B (CHB), 188 HBV-related decompensated cirrhosis (DC), 214 HBV-related hepatocellular carcinoma (HCC) and 169 healthy controls (HC). In the case-control study, one novel locus significantly associated with CHB (SNP: rs1264473, Gene: GRHL2, P = 1.57 × 10-6) and HCC (SNP: rs2833856, Gene: EVA1C, P = 1.62 × 10-6; SNP: rs4661093, Gene: ETV3, P = 2.26 × 10-6). In the trend study across progressive stages post HBV infection, one novel locus (SNP: rs1537862, Gene: LACE1, P = 1.85 × 10-6), and three MHC loci (HLA-DRB1, HLA-DPB1, HLA-DPA2) showed significant increased progressive risk from ASPI to CHB. Underlying the evolutionary study of HBV-related genes in public database, the derived allele of two HBV clearance related loci, rs3077 and rs9277542, are under strong selection in European population.

CONCLUSIONS

In this study, we identified several novel candidate genes associated with individual HBV infectious outcomes, progressive stages, and liver enzymes. Two SNPs that show selective significance (HLA-DPA1, HLA-DPB1) in non-East Asian (European, American, South Asian) versus East Asian, indicating that host genetic factors contribute to the ethnic disparities of susceptibility of HBV infection. Taken together, these findings provided a new insight into the role of host genetic factors in HBV related outcomes and progression.

Hepatitis B virus American genotypes: Pathogenic variants ?

Hepatitis B virus (HBV) chronic infection is responsible for almost 900.000 deaths each year, due to cirrhosis or hepatocellular carcinoma (HCC). Ten HBV genotypes have been described (A-J). HBV genotype F and H circulate in America. HBV genotypes have been further classified in subgenotypes. There is a strong correlation between the genetic admixture of the American continent and the frequency of genotypes F or H: a high frequency of these genotypes is found in countries with a population with a higher ratio of Amerindian to African genetic admixture. The frequency of occult HBV infection in Amerindian communities from Latin America seems to be higher than the one found in other HBV-infected groups, but its association with American genotypes is unknown. There is growing evidence that some genotypes might be associated with a faster evolution to HCC. In particular, HBV genotype F has been implicated in a frequent and rapid progression to HCC. However, HBV genotype H has been associated to a less severe progression of disease. This study reviews the diversity and frequency of autochthonous HBV variants in the Americas and evaluates their association to severe progression of disease. Although no significant differences were found in the methylation pattern between different genotypes and subgenotypes of the American types, basal core promoter mutations might be more frequent in some subgenotypes, such as F1b and F2, than in other American subgenotypes or genotype H. F1b and probably F2 may be associated with a severe presentation of liver disease as opposed to a more benign course for subgenotype F4 and genotype H. Thus, preliminary evidence suggests that not all of the American variants are associated with a rapid progression to HCC.

Recent and occult hepatitis B virus infections among blood donors in the United States

BACKGROUND

Characteristics of US blood donors with recent (RBI) or occult (OBI) hepatitis B virus (HBV) infection are not well defined.

METHODS

Donors with RBI and OBI were identified by nucleic acid and serologic testing among 34.4 million donations during 2009-2015. Consenting donors were interviewed and their HBV S-gene sequenced.

RESULTS

The overall rate of HBV-infected donors was 7.95 per 100,000; of these, 0.35 per 100,000 and 1.70 per 100,000 were RBI and OBI, respectively. RBI (n = 120) and OBI (n = 583) donors constituted 26% of all HBV-infected (n = 2735) donors. Detection of HBV DNA in 92% of OBI donors required individual donation nucleic acid testing. Donors with OBI compared to RBI were older (mean age, 48 vs 39 years; p < 0.0001) with lower median viral loads (9 vs. 529 IU/mL; p < 0.0001). A higher proportion of OBI than RBI donors were born or resided in an endemic country (39% vs. 5%; p = 0.0078). Seventy-seven percent of all RBI and OBI donors had multiple sex partners, an HBV-risk factor. Of 40 RBI and 10 OBI donors whose S gene was sequenced, 33 (83%) and 6 (60%), respectively, carried HBV subgenotype A2; 18 (55%) and 2 (33%), respectively, shared an identical sequence. Infection with 1 or more putative HBV-immune-escape mutants was identified in 5 (50%) of OBI but no RBI donors.

CONCLUSION

RBI and OBI continue to be identified at low rates, confirming the importance of comprehensive HBV DNA screening of US blood donations. HBV-infected donors require referral for care and evaluation and contact tracing; their HBV strains may provide important information on emergent genotypes.

Permissive, in vitro replication of hepatitis B virus genotype E

A cloned stable cell line, HepG2-HBVE6, was established following transfection of HepG2 cells with a retroviral plasmid into which a 1.1-fold genomic construct of hepatitis B virus (HBV) belonging to genotype E (HBV/E) was inserted. The cell line retains the entire HBV/E insert, and produces episomal HBV DNA. It expresses HBV pregenomic, preS1 and preS2/S transcripts, and sheds hepatitis B surface and e antigens as well as structures resembling HBV-subviral and Dane particles. The HepG2-HBVE6 cell line, in permitting recapitulation of the HBV life cycle, may be used for studying viral characteristics, therapeutic and preventative outcomes and for preparing reagents specific to HBV genotype E.

Epidemiology of Acute Hepatitis B in the United States From Population-Based Surveillance, 2006-2011

BACKGROUND

An estimated 20 000 new hepatitis B virus (HBV) infections occur each year in the United States. We describe the results of enhanced surveillance for acute hepatitis B at 7 federally funded sites over a 6-year period.

METHODS

Health departments in Colorado, Connecticut, Minnesota, Oregon, Tennessee, 34 counties in New York state, and New York City were supported to conduct enhanced, population-based surveillance for acute HBV from 2006 through 2011. Demographic and risk factor data were collected on symptomatic cases using a standardized form. Serum samples from a subset of cases were also obtained for molecular analysis.

RESULTS

In the 6-year period, 2220 acute hepatitis B cases were reported from the 7 sites. For all sites combined, the incidence rate of HBV infection declined by 19%, but in Tennessee incidence increased by 90%, mainly among persons of white race/ethnicity and those aged 40-49 years. Of all reported cases, 66.1% were male, 57.1% were white, 58.4% were aged 30-49 years, and 60.1% were born in the United States. The most common risk factor identified was any drug use, notably in Tennessee; healthcare exposure was also frequently reported. The most common genotype for all reported cases was HBV genotype A (82%).

CONCLUSIONS

Despite an overall decline in HBV infection, attributable to successful vaccination programs, a rise in incident HBV infection related to drug use is an increasing concern in some localities.

Recent population expansions of hepatitis B virus in the United States

The recent epidemic history of hepatitis B virus (HBV) infections in the United States is complex, as indicated by current disparity in HBV genotype distribution between acute and chronic hepatitis B cases and the rapid decline in hepatitis B incidence since the 1990s. We report temporal changes in the genetic composition of the HBV population using whole-genome sequences (n = 179) from acute hepatitis B cases (n = 1,206) identified through the Sentinel County Surveillance for Acute Hepatitis (1998 to 2006). HBV belonged mainly to subtypes A2 (75%) and D3 (18%), with times of their most recent common ancestors being 1979 and 1987, respectively. A2 underwent rapid population expansions in ca. 1995 and ca. 2002, coinciding with transient rises in acute hepatitis B notification rates among adults; D3 underwent expansion in ca. 1998. A2 strains from cases identified after 2002, compared to those before 2002, tended to cluster phylogenetically, indicating selective expansion of specific strains, and were significantly reduced in genetic diversity (P = 0.001) and frequency of drug resistance mutations (P = 0.001). The expansion of genetically close HBV A2 strains was associated with risk of infection among male homosexuals (P = 0.03). Incident HBV strains circulating in the United States were recent in origin and restricted in genetic diversity. Disparate transmission dynamics among phylogenetic lineages affected the genetic composition of HBV populations and their capacity to maintain drug resistance mutations. The tendency of selectively expanding HBV strains to be transmitted among male homosexuals highlights the need to improve hepatitis B vaccination coverage among at-risk adults.

IMPORTANCE

Hepatitis B virus (HBV) remains an important cause of acute and chronic liver disease globally and in the United States. Genetic analysis of HBV whole genomes from cases of acute hepatitis B identified from 1998 to 2006 in the United States showed dominance of genotype A2 (75%), followed by D3 (18%). Strains of both subtypes were recent in origin and underwent rapid population expansions from 1995 to 2000, indicating increase in transmission rate for certain HBV strains during a period of decline in the reported incidence of acute hepatitis B in the United States. HBV A2 strains from a particular cluster that experienced the most recent population expansion were more commonly detected among men who have sex with men. Vaccination needs to be stepped up to protect persons who remain at risk of HBV infection.

Molecular identification of hepatitis B virus genotypes/subgenotypes: revised classification hurdles and updated resolutions

The clinical course of infections with the hepatitis B virus (HBV) substantially varies between individuals, as a consequence of a complex interplay between viral, host, environmental and other factors. Due to the high genetic variability of HBV, the virus can be categorized into different HBV genotypes and subgenotypes, which considerably differ with respect to geographical distribution, transmission routes, disease progression, responses to antiviral therapy or vaccination, and clinical outcome measures such as cirrhosis or hepatocellular carcinoma. However, HBV (sub)genotyping has caused some controversies in the past due to misclassifications and incorrect interpretations of different genotyping methods. Thus, an accurate, holistic and dynamic classification system is essential. In this review article, we aimed at highlighting potential pitfalls in genetic and phylogenetic analyses of HBV and suggest novel terms for HBV classification. Analyzing full-length genome sequences when classifying genotypes and subgenotypes is the foremost prerequisite of this classification system. Careful attention must be paid to all aspects of phylogenetic analysis, such as bootstrapping values and meeting the necessary thresholds for (sub)genotyping. Quasi-subgenotype refers to subgenotypes that were incorrectly suggested to be novel. As many of these strains were misclassified due to genetic differences resulting from recombination, we propose the term "recombino-subgenotype". Moreover, immigration is an important confounding facet of global HBV distribution and substantially changes the geographic pattern of HBV (sub)genotypes. We therefore suggest the term "immigro-subgenotype" to distinguish exotic (sub)genotypes from native ones. We are strongly convinced that applying these two proposed terms in HBV classification will help harmonize this rapidly progressing field and allow for improved prophylaxis, diagnosis and treatment.

Hepatitis B virus infection among HIV-infected pregnant women in Malawi and transmission to infants

BACKGROUND & AIMS

The extent of HBV infection to infants of HBV/HIV-coinfected pregnant women in sub-Saharan Africa is unknown. The aim of this study was to assess prevalence of HBV infection among antiretroviral-naïve, HIV-infected pregnant women in Malawi and examine HBV transmission to their infants.

METHODS

Plasma from 2048 HIV-infected, Malawian women and their infants were tested for markers of HBV infection. Study participants were provided standard-of-care health services, which included administration of pentavalent vaccine to infants at 6, 10, and 14 weeks of age.

RESULTS

One-hundred and three women (5%) were HBsAg-positive; 70 of these HBsAg-positive women were also HBV-DNA-positive. Sixteen women (0.8%) were HBV-DNA-positive but HBsAg-negative. Five of 51 infants (9.8%) born to HBsAg-positive and/or HBV-DNA-positive women were HBV-DNA-positive by 48 weeks of age.HBV DNA concentrations of two infants of mothers who received extended lamivudine-containing anti-HIV prophylaxis were <4 log10 IU/ml compared to ⩾ 8 log10 IU/ml in three infants of mothers who did not.

CONCLUSIONS

HBV DNA was detected in nearly 10% of infants born to HBV/HIV-coinfected women. Antenatal testing for HIV and HBV, if instituted, can facilitate implementation of prophylactic measures against infant infection by both viruses.

Characterization of hepatitis B virus genotypes and quantitative hepatitis B surface antigen titres in North American tertiary referral liver centres

BACKGROUND & AIMS

Hepatitis B virus (HBV) genotype and quantitative hepatitis B surface antigen (qHBsAg) have been related to clinical outcome. In this nationwide cross-sectional study, we aimed to investigate the epidemiology and clinical significance of HBV genotype and qHBsAg in patients with chronic hepatitis B (CHB).

METHODS

Six hundred and thirty patients with CHB were seen in four urban tertiary referral centres in Canada. HBV genotype was determined by line probe assay (INNO-LIPA) and HBV DNA quantified by commercial PCR (Roche TaqMan, sensitivity <55 IU/ml or AMPLICOR, sensitivity <60 IU/ml). Titres of qHBsAg were determined by an in-house assay based on the WHO standard (calibration range 0.24-62.5 IU/ml).

RESULTS

In 630 patients (57% male, 69% Asian, median age 42 years), 21% were hepatitis B e antigen positive and the median alanine aminotransferase was 29 U/L. The HBV genotype distribution was A (16%), B (29%), C (31%), D (16%), E (6%). HBV genotype was strongly associated with ethnicity, but neither genotype nor qHBsAg correlated with the degree of fibrosis. In the treatment-naïve patients, the baseline qHBsAg levels correlated with HBV DNA (r = 0.2517, P < 0.0008). The median qHBsAg levels were lowest in patients with genotype B (P < 0.0001), but no significant correlation was noted with all other HBV genotypes.

CONCLUSIONS

In this large North American HBV epidemiological study, genotypes B and C were the most common; however, all genotypes (A-E) were observed with varied distribution nationwide. Baseline qHBsAg significantly correlated with HBV DNA and with HBV genotype B, but not with liver fibrosis.

Selective hepatitis B virus vaccination has reduced hepatitis B virus transmission in the Netherlands

BACKGROUND & AIMS

In the Netherlands, a selective hepatitis B virus (HBV) vaccination programme started in 2002 for men having sex with men, drug users, commercial sex workers and heterosexuals with frequent partner changes. We assessed the programme's effectiveness to guide policy on HBV prevention.

METHODS

We analysed reports of acute HBV infection in the Netherlands between 2004 and 2010 requesting serum from patients for HBV-genome S- and C-region sequencing. We used coalescence analyses to assess genetic diversity of nonimported genotype-A cases over time.

RESULTS

1687 patients with acute HBV infection were reported between 2004 and 2010. The incidence of reported acute HBV infection decreased from 1.8 to 1.2 per 100,000 inhabitants, mostly due to a reduction in the number of cases in men who have sex with men. Men were overrepresented among cases with an unknown route of transmission, especially among genotype A2 cases mainly associated with transmission through male homosexual contact. The genetic diversity of nonimported genotype-A strains obtained from men who have sex with men decreased from 2006 onwards, suggesting HBV incidence in this group decreased.

CONCLUSIONS

The selective HBV-vaccination programme for behavioural high-risk groups very likely reduced the incidence of HBV infection in the Netherlands mainly by preventing HBV infections in men who have sex with men. A considerable proportion of cases in men who did not report risk behaviour was probably acquired through homosexual contact. Our findings support continuation of the programme, and adopting similar approaches in other countries where HBV transmission is focused in high-risk adults.

Acute hepatitis B outbreaks in 2 skilled nursing facilities and possible sources of transmission: North Carolina, 2009-2010

OBJECTIVE

Acute hepatitis B virus (HBV) infections have been reported in long-term care facilities (LTCFs), primarily associated with infection control breaks during assisted blood glucose monitoring. We investigated HBV outbreaks that occurred in separate skilled nursing facilities (SNFs) to determine factors associated with transmission.

DESIGN

Outbreak investigation with case-control studies.

SETTING

Two SNFs (facilities A and B) in Durham, North Carolina, during 2009-2010.

PATIENTS

Residents with acute HBV infection and controls randomly selected from HBV-susceptible residents during the outbreak period.

METHODS

After initial cases were identified, screening was offered to all residents, with repeat testing 3 months later for HBV-susceptible residents. Molecular testing was performed to assess viral relatedness. Infection control practices were observed. Case-control studies were conducted to evaluate associations between exposures and acute HBV infection in each facility.

RESULTS

Six acute HBV cases were identified in each SNF. Viral phylogenetic analysis revealed a high degree of HBV relatedness within, but not between, facilities. No evaluated exposures were significantly associated with acute HBV infection in facility A; those associated with infection in facility B (all odds ratios >20) included injections, hospital or emergency room visits, and daily blood glucose monitoring. Observations revealed absence of trained infection control staff at facility A and suboptimal hand hygiene practices during blood glucose monitoring and insulin injections at facility B.

CONCLUSIONS

These outbreaks underscore the vulnerability of LTCF residents to acute HBV infection, the importance of surveillance and prompt investigation of incident cases, and the need for improved infection control education to prevent transmission.

Hepatitis B virus transmissions associated with a portable dental clinic, West Virginia, 2009

BACKGROUND

Although hepatitis B virus (HBV) transmission in dental settings is rare, in 2009 a cluster of acute HBV infections was reported among attendees of a two-day portable dental clinic in West Virginia.

METHODS

The authors conducted a retrospective investigation by using treatment records and volunteer logs, interviews of patients and volunteers with acute HBV infection as well as of other clinic volunteers, and molecular sequencing of the virus from those acutely infected.

RESULTS

The clinic was held under the auspices of a charitable organization in a gymnasium staffed by 750 volunteers, including dental care providers who treated 1,137 adults. Five acute HBV infections-involving three patients and two volunteers-were identified by the local and state health departments. Of four viral isolates available for testing, all were genotype D. Three case patients underwent extractions; one received restorations and one a dental prophylaxis. None shared a treatment provider with any of the others. One case volunteer worked in maintenance; the other directed patients from triage to the treatment waiting area. Case patients reported no behavioral risk factors for HBV infection. The investigation revealed numerous infection control breaches.

CONCLUSIONS

Transmission of HBV to three patients and two volunteers is likely to have occurred at a portable dental clinic. Specific breaches in infection control could not be linked to these HBV transmissions.

PRACTICAL IMPLICATIONS

All dental settings should adhere to recommended infection control practices, including oversight; training in prevention of bloodborne pathogens transmission; receipt of HBV vaccination for staff who may come into contact with blood or body fluids; use of appropriate personal protective equipment, sterilization and disinfection procedures; and use of measures, such as high-volume suction, to minimize the spread of blood.