Genotyping of acute HBV isolates from England, 1997–2001

Seroprevalence of immunity to hepatitis A and hepatitis B among gay, bisexual and other men who have sex with men (GBMSM) attending sexual health clinics in London and Leeds, England, 2017-2018

OBJECTIVES

Although hepatitis A virus (HAV) and hepatitis B virus (HBV) immunisation is recommended in the UK for gay, bisexual and other men who have sex with men (GBMSM), data on immunisation coverage are limited. We aimed to determine the seroprevalence of HAV and HBV immunity among a sample of GBMSM attending sexual health services (SHS) in England.

METHODS

Residual serum samples from HIV/syphilis testing for adult GBMSM attending eight SHS in London and one in Leeds were tested for markers of HAV immunity (HAV IgG) and HBV immunity (anti-HBs) using an unlinked anonymous approach. We estimated seroprevalence of HAV and HBV immunity overall and stratified by individuals' characteristics, which we obtained from the Genitourinary Medicine Clinic Activity Dataset Sexually Transmitted Infection (STI) Surveillance System. We used logistic regression to calculate crude and adjusted ORs between seropositivity and demographic and clinical characteristics.

RESULTS

Seroprevalence of immunity to HAV (74.5% of 2577) and HBV (77.1% of 2551) was high. In adjusted analysis, HAV IgG seroprevalence varied by clinic and WHO region of birth (global p<0.001 for each), increased with older age (ORs of 1.50 (95% CI 1.18 to 1.86), 2.91 (2.17 to 3.90) and 3.40 (2.44 to 4.75) for ages 26-35, 36-45 and >46 vs 18-25 years (global p<0.001), was higher in those with an STI in the past year (1.58 (1.25 to 2.00); p<0.001) and those who were living with HIV (1.82 (1.25 to 2.64); p<0.001). Anti-HBs seroprevalence varied by clinic (global p<0.001), increased with older age (global p<0.001) and was higher in those with an STI in the past year (1.61 (1.27 to 2.05); p<0.001).

CONCLUSION

Our findings provide a baseline seroprevalence from which to monitor serial levels of immunity to HBV and HAV in GBMSM accessing SHS. Levels of immunity for both viruses are high, noting samples were taken after recent widespread outbreaks and vaccination campaigns. High vaccine coverage in all GBMSM should be maintained to prevent further outbreaks.

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.

Phylogenetic analysis reveals three distinct epidemiological profiles in Dutch and Flemish blood donors with hepatitis B virus infection

During 2006-2016, hepatitis B virus (HBV) was detected in nearly 400 blood donors in the Netherlands and Flanders. Donor demographics and self-reported risk factors as disclosed during the donor exit interview were compared to HBV phylogenies of donor and reference sequences. First-time donors with chronic HBV-infection were often immigrants (67%) infected with genetically highly diverse strains of genotypes A (32%), B (8%), C (6%), D (53%) and E to H (1%). Each subtype was strongly associated with donor ethnicity. In contrast, 57/62 (93%) of acute/recent HBV infections occurred among indigenous donors, of whom 67% was infected with one specific widely circulating epidemic HBV-A2 lineage. HBV typing identified three distinct epidemiological profiles: the import of chronic HBV infections through migration, longstanding transmission of non-epidemic HBV-A2 strains within western-Europe, and the active transmission of one epidemic HBV-A2 strain most likely fueled by sexual risk behavior.

Characterization of Acute and Chronic Hepatitis B Virus Genotypes in Canada

Objective

The prevalence and distribution of hepatitis B virus (HBV) genotypes in Canada is not known. Genotypic analysis may contribute to a better understanding of HBV strain distribution and transmission risk.

Methods

HBV surface antigen (HBsAg) positive samples of acute (n = 152) and chronic (n = 1533) HBV submitted for strain analysis or reference genotype testing between 2006 and 2012 were analyzed. The HBsAg coding region was amplified to determine the HBV genotype by INNO-LiPA assay or sequence analysis. Single and multivariate analyses were used to describe genotypes’ associations with known demographic and behavioral risk factors for 126 linked cases of acute HBV.

Results

Nine genotypes were detected (A to I), including mixed infections. Genotype C (HBV/C) dominated within chronic infections while HBV/D and A prevailed among acute HBV cases. History of incarceration and residing with a chronic HBV carrier or injection drug user were the most frequently reported risks for acute HBV infection. Over time, HBV/A increased among both acute and chronic infections, and HBV/C and HBV/D decreased among chronic infections.

Conclusion

Chronic and acute HBV genotypes in Canada differ in the relative distribution and their associations with known risk factors, suggesting different routes of transmission and clinical progression of infection.

Molecular epidemiology of hepatitis B virus genotypes circulating in acute hepatitis B patients in the Campania region

Fifty-three HBV-DNA-positive patients with symptomatic acute hepatitis B were enrolled from 1999 to 2010 to evaluate molecular and phylogenetic changes in HBV in southern Italy. HBV polymerase region was evaluated by direct sequencing in plasma samples obtained at first observation. Different data sets were aligned and a phylogenetic tree was inferred using PhyML program. Statistical robustness was confirmed with a bootstrap analysis. A Bayesian Markov chain Monte Carlo method and a Bayesian skyline plot were used to estimate the evolution of our samples. The dN/dS rate (ω) was estimated by the maximum likelihood approach to investigate the presence of codons under positive selection. The MacClade program was used to test viral gene out/in flow only among HBV-D3 subgenotype patients with different risk factors. Of the 53 patients, 83% were born in Italy and 17% were foreigners. HBV genotype D was prevalent (64.1%), followed by genotype A (26.4%), E (3.8%), and F (5.7%). The prevalent subgenotype was D3 (70.6%). The Bayesian tree of the 24 D3 subgenotypes showed two main clades both dated 1994; 40% of viral gene flow observed was from intravenous drugs users and heterosexual patients. Phylogenetic analysis of HBV isolates showed that HBV-D3 remains the prevalent genotype, but also subgenotype A2 has become frequent in southern Italy. This may be of clinical relevance in years to come, since patients with HBV-genotype-A chronic infection less frequently than those with genotype D develop HBeAg-negative chronic hepatitis and respond more frequently to alfa-interferon treatment.

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 epidemiology and clinical characteristics of hepatitis B identified through the French mandatory notification system

BACKGROUND & AIMS

Strains responsible for acute hepatitis B infections (AHB) in France have not been characterized. This study was first designed to analyze the molecular epidemiology of AHB and second to describe the differences between AHB and chronic hepatitis B (CHB) exacerbations.

METHODS

This prospective study was based on the French mandatory notification system for AHB. 147 samples corresponding to declared cases were shipped to a central laboratory for classification as AHB or CHB according to the level of anti-HBc IgM and anti-HBc avidity.

RESULTS

Based on biological marker values and file examination, 75 cases (59%) were classified as AHB. Independently of the acute or chronic status, genotype A (57%), D (22%) and E (14%) were the most prevalent and no phylogenetic clustering was observed among HBV sequences (n=68). Precore or basal core-promoter variants were not particularly associated with disease severity but were more prevalent in CHB. No antiviral resistant strains or immune-escape HBsAg was observed. HBV viral loads in AHB or CHB were comparable but with opposite distributions. ALT levels reached 10 times the upper normal value in 94% of AHB but only in 24% of CHB.

CONCLUSIONS

After rigorous classification, no major difference at the genetic level was found between HBV strains isolated from AHB and CHB. Absence of potentially deleterious variant detection is reassuring. When based upon HBsAg and anti-HBc IgM determination, AHB notification may falsely include more than 40% CHB, leading to an important risk of bias in national surveillance programs of AHB.

Evaluation of anti-HBV drug resistant mutations among patients with acute symptomatic hepatitis B in the United States

BACKGROUND & AIMS

Reported HBV drug resistance mutations among previously untreated patients with chronic hepatitis B are variable. Whether resistant HBV strains are transmitted in the acute setting is uncertain. We sought to document the presence of antiviral resistance (AVR) mutations in patients with acute HBV (AHB) infection.

METHODS

AHB infection was defined by HBsAg/IgM anti-HBc positivity, ALT>10X ULN and compatible clinical history. The TRUGENE HBV kit was used to perform genotyping and direct sequencing of the viral polymerase. INNO-LiPA HBV DRv2 and DRv3 were used to detect AVR mutations. Clonal sequencing was conducted on selected specimens.

RESULTS

Twenty-three patients were evaluated (mean age, 43 years; 54% male; 39% African American, 39% Caucasian, 13% Hispanic and 4% Asian). The mean peak ALT was 1554.2IU/L and mean peak total serum bilirubin was 12 mg/dl. The HBV DNA median viral load (N = 15) was 5.14 log(10)IU/ml. Nineteen patients were genotype A, and 1 each were genotype C, D, E and G. HBV drug resistance mutations were not detected by direct sequencing or INNO-LiPA. Clonal sequencing was conducted on 192 clones isolated from three patients and showed rtA181T, rtM250V and rtS202G mutations at an overall frequency of 1.54%, 1.39%, and 1.67% respectively.

CONCLUSIONS

We detected adefovir/lamivudine and entecavir relevant mutations in a minor population (<2%) of viral clones by clonal sequencing only. The clinical significance of these mutations is uncertain and may represent small populations of quasi-species vs. transmission of drug resistant strains.

The diversity and management of chronic hepatitis B virus infections in the United Kingdom: a wake-up call

BACKGROUND

Through migration, diversity of chronic hepatitis B virus (HBV) infection has changed, affecting disease burden and control. We describe clinical and viral characteristics of chronic HBV in the United Kingdom.

METHODS

A total of 698 individuals with chronic HBV infection were recruited from referral liver centers. Demographic, clinical, and laboratory data were collected.

RESULTS

Sixty-one percent of patients were male, 80% were not born in the United Kingdom, and the largest ethnicity was East/Southeast Asian (36%). Twenty-two percent were hepatitis B e antigen (HBeAg) seropositive; 20.4% (59/289) had cirrhosis and 10 (1.7%) had hepatocellular carcinoma. Genotype D was most common (31%) followed by A, C, B, and E (20%, 20%, 19%, and 9%, respectively). Genotype was significantly associated with country of birth, length of time in the United Kingdom, HBeAg status, and precore and basal core promoter mutations. One-third were on treatment, with men independently more likely to be treated. Only 18% of those on treatment were on recommended first-line therapies, and 30% were on lamivudine monotherapy. Among treated individuals, 27% had antiviral drug resistance. Testing rates for human immunodeficiency virus, hepatitis C virus, and delta coinfections were low.

CONCLUSIONS

We demonstrated diversity of chronic HBV infections in UK patients, suggesting that optimal management requires awareness of the variable patterns of chronic HBV in countries of origin. We also found less-than-optimal clinical management practices, possible gender-based treatment bias, and the need to improve testing for coinfections.

Molecular epidemiology of a large community-based outbreak of hepatitis B in Bristol, U.K

BACKGROUND

A large outbreak of hepatitis B virus (HBV) infection in the U.K. occurred between 2001 and 2005 in Bristol, U.K.

OBJECTIVES

To identify HBV strains circulating amongst risk groups in the HBV outbreak cohort.

STUDY DESIGN

Cross-sectional study of acute HBV outbreak cases in Bristol.

RESULTS

HBV sequences from sera of 95 of the 237 cases (40%) were characterised. The majority of cases (77%) were found to carry an HBV variant belonging to genotype D, designated HBV(BV). Eighty-eight percent (36/41) of sequences from injection drug users were HBV(BV) as were 70% (19/27) from those with heterosexual intercourse as the primary identified risk factor. Of 15 sequences characterised from cases of pre-outbreak acute or chronic hepatitis B residing in Bristol, 40% also carried HBV(BV); the earliest was from a case identified in 1994.

CONCLUSION

The findings from this study link the spread of HBV(BV) from injecting drug users to the general population through heterosexual intercourse during the outbreak. The molecular sequencing of specimens from this outbreak reports the emergence of HBV(BV), a HBV strain circulating in Bristol and South West England, as the cause of one of the largest outbreaks of acute hepatitis B in the U.K.

HBV primary drug resistance in newly diagnosed HIV-HBV-coinfected individuals in Spain

BACKGROUND

The wide use of lamivudine (3TC) as oral therapy for chronic HBV infection has favoured the selection and circulation of 3TC-resistant HBV strains worldwide. Although transmission of 3TC-resistant HBV variants has been reported only sporadically, few studies have been conducted in the HIV population where exposure to 3TC has been greater forming part of antiretroviral therapy (ART) regimens.

METHODS

All individuals positive for serum hepatitis B surface antigen (HBsAg), newly diagnosed with HIV-1 infection, naive to ART and enrolled in the Spanish HIV cohort (CoRIS) since 2004 were identified. The HBV polymerase gene was sequenced and drug resistance mutations were characterized retrospectively in stored frozen plasma specimens.

RESULTS

From 4,419 ART-naive HIV-1-infected individuals, 223 (5.1%) were positive for serum HBsAg. Baseline stored sera were available for 84 patients, of whom 73 could be characterized virologically. This population was mainly represented by men who had sex with men (52.1%), native Spaniards (65.7%) and Latin Americans (16.4%). The mean age was 36 years, mean CD4(+) T-cell count 375 cells/mm(3) and mean plasma HIV RNA 4.5 log(10) copies/ml. The HBV genotype distribution was 64% A, 20% F, 12% D and 4% others. Drug-resistant mutations in the HBV polymerase were found in four (5.5%) patients: two harboured rtL180M, one rtL80V and one rtV173L.

CONCLUSIONS

The rate of primary drug resistance in HBV among newly diagnosed HIV-HBV-coinfected patients in Spain is currently low (5.5%) and restricted to 3TC. Thus, HBV drug resistance testing before prescription of oral antiviral therapy is not warranted, although periodic surveillance might be recommended.

Development of a novel genotype-specific loop-mediated isothermal amplification technique for Hepatitis B virus genotypes B and C genotyping and quantification

BACKGROUND

There is the need for a rapid, economical method for genotyping Hepatitis B virus (HBV) to support clinical practice.

OBJECTIVES

To develop a novel HBV genotyping process using genotype specific loop mediated isothermal amplification (LAMP).

STUDY DESIGN

HBV genotypes B and C specific LAMP methods were evaluated using standard panel. A comparative analysis of the LAMP test against Taqman assay using 105 clinical samples, was undertaken to evaluate the quantitation capacity of the method. 111 clinical samples were used to test the clinical applicability of the genotype specific LAMP method. The results were compared with those obtained by real-time PCR based genotyping and sequencing.

RESULTS

Using genotype-specific primers, the LAMP assay correctly identified all predefined genotypes B and C, and no cross-reaction was observed. Real-time format of this assay provides simultaneous identification and quantification of genotypes B and C. The detection sensitivity of the method was found to be 323 and 515 copies/ml for genotypes B and C specific LAMP assay respectively. High correlation (R(2)=0.91) and good agreement between the LAMP method and the real-time PCR test were achieved for HBV quantitation. Samples from 111 HBV-infected patients were genotyped with LAMP, revealing 53% HBV as genotype B, 36% as genotype C, and 12% as mixed genotypes B and C. LAMP method showed coincidence rates of 96.7% with the real-time PCR genotyping results.

CONCLUSION

This approach is a promising tool for HBV genotyping and quantitation. It appears to be useful for routine clinical practice even in field investigation.

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

BACKGROUND

Knowledge of the genotypic distribution of hepatitis B virus (HBV) facilitates epidemiologic tracking and surveillance of HBV infection as well as prediction of its disease burden. In the United States, HBV genotyping studies have been conducted for chronic but not acute hepatitis B.

METHODS

Serum samples were collected from patients with acute hepatitis B cases reported from the 6 counties that participated in the Sentinel Counties Study of Acute Viral Hepatitis from 1999 through 2005. Polymerase chain reaction followed by nucleotide sequencing of a 435-base pair segment of the HBV S gene was performed, and the sequences were phylogenetically analyzed.

RESULTS

Of 614 patients identified with available serum samples, 75% were infected with genotype A HBV and 18% were infected with genotype D HBV. Thirty-two percent of genotype A sequences constituted a single subgenotype A2 cluster. The odds of infection with genotype A (vs with genotype D) were 5 times greater among black individuals than among Hispanic individuals (odds ratio [OR], 5; 95% confidence interval [CI], 2.3-10.7). The odds of infection with genotype A were 49, 8, and 4 times greater among patients from Jefferson County (Alabama), Pinellas County (Florida), and San Francisco (California), respectively, than among those living in Denver County (Colorado). Genotype A was less common among recent injection drug users than it was among non-injection drug users (OR, 0.2; 95% CI, 0.1-0.4).

CONCLUSIONS

HBV genotype distribution was significantly associated with ethnicity, place of residence, and risk behavior.

Molecular characterization and phylogenetic analysis of full-genome HBV subgenotype D3 sequences from Serbia

Hepatitis B virus (HBV) is classified into 8 genotypes with distinct geographical distribution. Genotype D (HBV/D) has the widest distribution area and is comprised of 7 subgenotypes. Subgenotypes D1, D2 and D3 appear worldwide, while D4-D7 have a more restricted distribution. Within the Mediterranean area, HBV/D and subgenotype D3 are the most prevalent. The purpose of this study was to characterize the full genome of Serbian HBV/D3 isolates by comparison and phylogenetic analysis with HBV/D3 sequences (66 samples) found in GeneBank/DDBJ databases from different parts of the world. Isolates were obtained from three patients diagnosed with chronic hepatitis B (HBsAg+). All three isolates have two very rare nucleotide substitutions, A929T and T150A, which indicate the same ancestor. Phylogenetic analysis of HBV/D3 genome sequences throughout the world follows an ethno-geographical origin of isolates with rare exceptions, which could be explained by human travelling and migration. The geographically close but ethnically different Serbian and Italian isolates clustered in the same subnode, and on a common branch with strains from Northern Canada. To test the apparently close HBV phylogenetic relationship between completely separated patients from Serbia and Northern Canada we analyzed in depth a 440 bp region of the HBsAg from Canadian (n=73) and Serbian (n=70) isolates. The constructed parsimony tree revealed that strains from Serbia and Northern Canada fell along the same branch which indicates independent evolution within regions of each country. Considering that HBsAg sequence has limited variability for phylogenetic analyses, our hypothesis needs further confirmation with more HBV complete genome sequences.

Molecular characterization of the Hepatitis B virus genotypes in Colombia: a Bayesian inference on the genotype F

Hepatitis B is a worldwide health problem affecting about 2 billion people and more than 350 million are chronic carriers of the virus. Nine HBV genotypes (A to I) have been described. The geographical distribution of HBV genotypes is not completely understood due to the limited number of samples from some parts of the world. One such example is Colombia, in which few studies have described the HBV genotypes. In this study, we characterized HBV genotypes in 143 HBsAg-positive volunteer blood donors from Colombia. A fragment of 1306 bp partially comprising HBsAg and the DNA polymerase coding regions (S/POL) was amplified and sequenced. Bayesian phylogenetic analyses were conducted using the Markov Chain Monte Carlo (MCMC) approach to obtain the maximum clade credibility (MCC) tree using BEAST v.1.5.3. Of all samples, 68 were positive and 52 were successfully sequenced. Genotype F was the most prevalent in this population (77%) - subgenotypes F3 (75%) and F1b (2%). Genotype G (7.7%) and subgenotype A2 (15.3%) were also found. Genotype G sequence analysis suggests distinct introductions of this genotype in the country. Furthermore, we estimated the time of the most recent common ancestor (TMRCA) for each HBV/F subgenotype and also for Colombian F3 sequences using two different datasets: (i) 77 sequences comprising 1306 bp of S/POL region and (ii) 283 sequences comprising 681 bp of S/POL region. We also used two other previously estimated evolutionary rates: (i) 2.60 × 10(-4)s/s/y and (ii) 1.5 × 10(-5)s/s/y. Here we report the HBV genotypes circulating in Colombia and estimated the TMRCA for the four different subgenotypes of genotype F.

Factors affecting the changes in molecular epidemiology of acute hepatitis B in a Southern Italian area

To explore changes in molecular epidemiology of acute viral hepatitis B (AVH-B), hepatitis B virus (HBV) genotypes were determined by direct sequencing of the Pre-S-S region in 123 consecutive patients, with AVH-B observed in Naples or its surroundings in the last decade (group AVH-B) and in 123 HBV chronic carriers [chronic carrier of HBV (CC-B) group] from the same areas, who had been hepatitis B surface antigen-positive for more than 10 years. Genotype D was less frequently detected in patients with AVH-B than in those in the CC-B group (76.4%vs 97.5%, P < 0.0001). In the AVH-B group, intravenous drug addiction (IVDA) was the prevalent risk factor (55.3%) for acquiring HBV in the 94 patients with HBV genotype D, but it was rarely recorded (6.9%) in the 29 patients with genotypes non-D (P < 0.0001); unsafe sexual intercourse was prevalent in patients with genotype non-D (72.3%) and less frequent in those with genotype D (28.8%, P < 0.005). In the AVH-B group, the prevalence of non-D genotypes increased during the observation period from 11.1% in 1999-2003 to 41.1% in 2004-2008 (P < 0.0005), paralleling the increase in the prevalence of patients with unsafe sexual intercourse; similarly, the progressive decrease in IVDA paralleled the decrease in the prevalence of genotype D (from 88.3% in 1999-2003 to 11.7% in 2004-2008). The prevalence of HBV non-D genotypes recorded in the last 10 years in AVH-B in this area shows a progressive increase, most probably because of recent changes in HBV epidemiology, namely, the HBV mass vaccination campaign and increased immigration from areas with high HBV endemicity.

Migrants and emerging public health issues in a globalized world: threats, risks and challenges, an evidence-based framework

International population mobility is an underlying factor in the emergence of public health threats and risks that must be managed globally. These risks are often related, but not limited, to transmissible pathogens. Mobile populations can link zones of disease emergence to lowprevalence or nonendemic areas through rapid or high-volume international movements, or both. Against this background of human movement, other global processes such as economics, trade, transportation, environment and climate change, as well as civil security influence the health impacts of disease emergence. Concurrently, global information systems, together with regulatory frameworks for disease surveillance and reporting, affect organizational and public awareness of events of potential public health significance. International regulations directed at disease mitigation and control have not kept pace with the growing challenges associated with the volume, speed, diversity, and disparity of modern patterns of human movement. The thesis that human population mobility is itself a major determinant of global public health is supported in this article by review of the published literature from the perspective of determinants of health (such as genetics/biology, behavior, environment, and socioeconomics), population-based disease prevalence differences, existing national and international health policies and regulations, as well as inter-regional shifts in population demographics and health outcomes. This paper highlights some of the emerging threats and risks to public health, identifies gaps in existing frameworks to manage health issues associated with migration, and suggests changes in approach to population mobility, globalization, and public health. The proposed integrated approach includes a broad spectrum of stakeholders ranging from individual health-care providers to policy makers and international organizations that are primarily involved in global health management, or are influenced by global health events.

Does hepatitis B virus (HBV) genotype influence the clinical outcome of HBV infection?

Between 5 and 10% of adults infected with the hepatitis B virus (HBV) develop a chronic infection lasting longer than 6 months, which may lead to advanced liver disease. HBV can be classified into six genotypic families: A, B, C, D, E and F, but only genotypes A and D are significantly represented in western Europe, where they account for some 90% of cases of infection with HBV. In the present study, we investigated a possible association between HBV genotype A or D and clinical outcome of the infection. We compared the prevalence of these genotypes in a group of patients with chronic active hepatitis to that of a group with acute resolving hepatitis. In patients with chronic active hepatitis, genotype A was found in 28 of 35 patients and genotype D in only four. The remaining three patients were infected with genotype non-A, non-D. In contrast, genotype D was found in 24 of 30 patients with acute hepatitis, whilst genotype A was found in only three patients of this group. Three were infected with genotype non-A, non-D. Our results show a clear association between genotype A and chronic outcome (Ficher's exact test: two-sided P-value, P < 0.0001). They suggest that HBV genotypes may play a role in the virus-host relationship. Possible mechanisms for such a role are discussed.