Eight years of hepatitis B vaccination in Colombia with a recombinant vaccine: factors influencing hepatitis B virus infection and effectiveness

Factors associated with hepatitis B virus infection in indigenous communities of Colombia

Introduction. Colombia is home to 2 million indigenous people who live in conditions of poverty and with health deficiencies, making them vulnerable to contracting hepatitis B (HBV). Amazonas has a high virus prevalence, and there are barriers to accessing vaccination; thus, part of the population is susceptible to infection. Objective. To identify factors associated with HBV in Colombian indigenous people. Materials and Methods. A case-control study of people over 18 years from four departments of Colombia. Cases were identified through the national hepatitis B notification registry (2015-2022). Controls were selected and matched to cases (2:1) by age, sex, ethnicity, and department. Sociodemographic characteristics, factors associated with contact with body fluids, cultural practices, and vaccination history were identified by means of a survey. The ethics committee of the Universidad de Antioquia approved the project. Results. Seventy five cases and 150 controls from 13 ethnic groups were surveyed. Amazonas contributed 49% of participants, 83% were women, and the median age of cases was 30 years (IQ range: 27-37). The associated factors were a family history of hepatitis B [adjusted OR: 2.61 (95% CI: 1.09-6.27)] and, in women, the number of pregnancies [adjusted OR: 1.61 (95% CI 1.02- 2.54)]. The vaccination history showed a protective effect, but the association was not significant. Conclusion. Aspects associated with family life and unprotected sexual relations seem to be responsible for the potential transmission of the virus. It was not possible to identify associated cultural practices. Innovative and differential strategies are required for indigenous people to achieve a reduction of HBV.

Hepatitis B Vaccine: Four Decades on

Hepatitis B virus is a substantial contributor to cirrhosis and hepatocellular carcinoma (HCC) globally. Vaccination is the most effective method for prevention of hepatitis B and its associated morbidity and mortality, and the only method to prevent infection with hepatitis D virus. The hepatitis B vaccine has been used worldwide for more than four decades; it is available in a single- or triple-antigen form and in combination with vaccines against other infections. Introduction of the vaccine and administration at birth led to sustained decline in mother-to-child transmission, chronic hepatitis B, and HCC, however, global birth dose coverage remains suboptimal. In this review we will discuss different hepatitis B vaccine formulations and schedules, vaccination guidelines, durability of the response, and vaccine escape mutants, as well as the clinical and economic benefits of vaccination.

High coverage and timeliness of vaccination of children under 6 years of age in Risaralda, Colombia

This study determined the coverage and timeliness of immunization in children <6 y from Risaralda, Colombia. A retrospective cross-sectional study evaluated data from a vaccination coverage and timeliness verification survey conducted in 2019, including 2457 children <6 y from Risaralda, Colombia. Variables included demographics, a record of vaccinations included in the Colombian Vaccination Plan, and date of immunization. Vaccination was defined as timely until 29 d after the day established by the plan. Coverage was over 95% for all vaccinations, except the boosters of diphtheria/pertussis/tetanus (DTP) and oral polio at 18 months (91.0%), influenza (85.6%), and yellow fever (49.2%). Most surveyed children demonstrated very high timeliness of vaccination, with values close to, or over, 90%, although there were exceptions for pentavalent (DTP+Haemophilus influenzae type B+hepatitis B) and polio vaccines at 6 months (79.4%), influenza (85.6%), and yellow fever (49.2%). Before the COVID-19 pandemic, Colombian Vaccination Plan demonstrated high coverage and timeliness of vaccination of children <6 y of age; however, timeliness for the third dose of DTP-Hib-HBV and polio showed opportunities for improvement.

Epidemiology and Genetic Diversity of Hepatitis B Virus and Hepatitis Delta Virus Infection in Indigenous Communities in Colombia

Despite the universal vaccination program, there are still regions and territories with a high prevalence of Hepatitis B Virus infection (HBV), such as the Amazon basin, where several indigenous communities live. Additionally, Hepatitis Delta Virus (HDV) is a defective that requires the hepatitis B surface antigen (HBsAg) for the assembly and release of de novo viral particles. Therefore, hepatitis D could be the result of HBV/HDV coinfection or HDV superinfection in individuals with chronic hepatitis B. Among the high prevalence HDV populations are indigenous communities of America. This study aims to describe and characterize the frequency of HBV and HDV infection, viral genotypes and HBV immune escape mutants in indigenous populations from different regions of Colombia. The diagnosis of hepatitis B and hepatitis D was confirmed by serological markers. Moreover, the HBV and HDV genome were amplified by PCR and RT-PCR, respectively, and, subsequently, the phylogenetic analysis was performed. We characterized 47 cases of chronic hepatitis B, 1 case of reactivation and 2 cases of occult hepatitis B infection (OBI). Furthermore, a high prevalence of HDV infection was identified in the study population (29.33%, 22/75) and the circulation of several HBV genotypes and subgenotypes (F1b, F3, F4, and D). Interestingly, this is the first report of the HDV genotype I circulation in this country. These findings demonstrated that HBV and HDV infections are still public health problems in indigenous communities in Colombia.

High prevalence of hepatitis B virus and low vaccine response in children and adolescents in Northeastern Brazil

Children have an increased likelihood of becoming carriers of the chronic hepatitis B virus. A total of 1,381 children and adolescents were assessed in five municipalities of Maranhao State, Brazil, for detection of anti-HBc, HBsAg and anti-HBs serologic markers and sociodemographic and behavioral features. Among those who were HBsAg negative and anti-HBc negative, the proportion of anti-HBs positives was calculated after the individuals had completed the vaccination schedule. The robust variance of the Poisson's regression model was used in order to have adjusted tables and calculate the prevalence ratio. Multivariate analysis was performed to identify the factors associated with the prevalence of anti-HBc with or without HBsAg and the vaccine response. It was observed that 163 children were anti-HBc positive and nine individuals were HBsAg positive. The factors associated with the infection were: municipality of residence (residing in Morros municipality or Humberto de Campos municipality), residence in a rural area, aged between 13 and 15 years old, and illicit drug use. The percentage of individuals who were anti-HBc negative and received all three doses of the vaccine was 48.5%. Among these, only 276 (38.9%) had antibodies at protective concentrations. In an adjusted analysis, Morros municipality presented an increased positivity of vaccine response (p < 0.001), and the age ranging between 6 and 10 years old presented a reduced frequency of response. This study reveals a high prevalence of current and past HBV infection within the targeted age group which, in addition to the low vaccination coverage and serological responses, raises concerns about the management of prevention measures, especially the quality of vaccination in these locations.

Progress towards the elimination of hepatitis B in children in Colombia: A novel two-phase study approach

The World Health Organization (WHO) has established a target to eliminate mother-to-child-transmission (EMTCT) of hepatitis B virus (HBV), defined as a prevalence of hepatitis B surface antigen (HBsAg) of ≤0.1% among children, by 2030. Using nationally representative serosurveys to verify achievement of this target requires large sample sizes and significant resources. We assessed the feasibility of a potentially more efficient two-phase method to verify EMTCT of HBV in Colombia. In the first phase, we conducted a risk assessment to identify municipalities at the highest risk of ongoing HBV transmission. We ranked the 1122 municipalities of Colombia based on the reports of HBV infection in pregnant women per 1000 population. Municipalities with ≥0.3 reports per 1000 persons (equating to the top quartile) were further assessed based on health facility birth rates, coverage with three doses of hepatitis B vaccine (HepB3) and seroprevalence data. Hepatitis B risk was considered to be further increased for municipalities with HepB3 coverage or health facility birth rate <90%. In the second phase, we conducted a multistage household serosurvey of children aged 5-10 years in 36 municipalities with the highest assessed HBV risk. HBsAg was not detected in any of 3203 children tested, yielding a 90% upper confidence bound of <0.1% prevalence. Coverage with HepB3 and hepatitis B birth dose was high at 97.5% and 95.6%, respectively. These results support the conclusion that Colombia has likely achieved EMTCT of HBV.

Global Perspective on Hepatitis B Virus Infections in the Era of Effective Vaccines

Hepatitis B virus (HBV) infection is a global health burden. The chronicity of this infection leads to complication such as cirrhosis and hepatocellular carcinoma, making it a leading cause of morbidity and mortality worldwide. Chronic infection commonly develops among those who acquire infection during childhood, hence the importance of effective implementation of HBV vaccination policies designed to eradicate chronic HBV. This article provides updated estimates of worldwide HBV disease prevalence and discusses how implementation of vaccination policies has affected HBV epidemiology.

Reactivation of hepatitis B virus infection in patients with hemo-lymphoproliferative diseases, and its prevention

Reactivation of hepatitis B virus (HBV) replication is characterized by increased HBV-DNA serum values of about 1 log or by HBV DNA turning positive if previously undetectable in serum, possibly associated with liver damage and seldom life-threatening. Due to HBV reactivation, hepatitis B surface antigen (HBsAg)-negative/anti-HBc-positive subjects may revert to HBsAg-positive. In patients with hemo-lymphoproliferative disease, the frequency of HBV reactivation depends on the type of lymphoproliferative disorder, the individual's HBV serological status and the potency and duration of immunosuppression. In particular, it occurs in 10%-50% of the HBsAg-positive and in 2%-25% of the HBsAg- negative/anti-HBc-positive, the highest incidences being registered in patients receiving rituximab-based therapy. HBV reactivation can be prevented by accurate screening of patients at risk and by a pharmacological prophylaxis with anti-HBV nucleo(t)sides starting 2-3 wk before the beginning of immunosuppressive treatment and covering the entire period of administration of immunosuppressive drugs and a long subsequent period, the duration of which depends substantially on the degree of immunodepression achieved. Patients with significant HBV replication before immunosuppressive therapy should receive anti-HBV nucleo(t)sides as a long-term (may be life-long) treatment. This review article is mainly directed to doctors engaged every day in the treatment of patients with onco-lymphoproliferative diseases, so that they can broaden their knowledge on HBV infection and on its reactivation induced by the drugs with high immunosuppressive potential that they use in the care of their patients.

Prevalence of Chronic Hepatitis B Virus Infection among Children in Haiti, 2017

In 2016, the World Health Assembly endorsed the Global Health Sector Strategy on Viral Hepatitis, which calls for elimination of hepatitis B virus (HBV) by 2030 (definition: ≤ 0.1% hepatitis B surface antigen [HBsAg] prevalence among children aged 5 years). The burden of chronic HBV infection among children in Haiti is unknown. We conducted a nationally representative cross-sectional serological survey among 5- to 7-year-old children based on a two-stage cluster design with two strata: West (includes metropolitan Port-au-Prince) and non-West (all other departments). We collected demographic, socioeconomic, and vaccination history data and tested for HBsAg using a rapid point-of-care test. We estimated HBsAg prevalence and evaluated the association of HBV infection with vaccination history, demographics, and socioeconomic characteristics. Of the 1,152 children, seven (0.5%, 95% CI: 0.2-1.2) were HBsAg positive. The HBsAg prevalence varied by region (West: 0.1%, 95% CI: 0.01-0.9; non-West: 0.7%, 95% CI: 0.2-1.9) (P = 0.1), gender (males: 0.7%, 95% CI: 0.2-2.4; females: 0.2%, 95% CI: 0.05-1.1) (P = 0.3), and caregiver's education level (none: 0.8%, 95% CI: 0.2-3.1; some or completed primary: 0.5%, 95% CI: 0.1-1.8; some secondary: 0.4%, 95% CI: 0.1-1.8; secondary and higher: 0.0%, 95% CI: 0-0), although the differences were not statistically significant. None of the HBsAg-positive children had documented vaccination with hepatitis B vaccine (HepB). Haiti's chronic HBV infection prevalence among children is low; however, it is above the elimination target. To reach elimination, Haiti needs to achieve high coverage with the three HepB doses and introduce a HepB birth dose.

Accelerating the elimination of viral hepatitis: a Lancet Gastroenterology & Hepatology Commission

Viral hepatitis is a major public health threat and a leading cause of death worldwide. Annual mortality from viral hepatitis is similar to that of other major infectious diseases such as HIV and tuberculosis. Highly effective prevention measures and treatments have made the global elimination of viral hepatitis a realistic goal, endorsed by all WHO member states. Ambitious targets call for a global reduction in hepatitis-related mortality of 65% and a 90% reduction in new infections by 2030. This Commission draws together a wide range of expertise to appraise the current global situation and to identify priorities globally, regionally, and nationally needed to accelerate progress. We identify 20 heavily burdened countries that account for over 75% of the global burden of viral hepatitis. Key recommendations include a greater focus on national progress towards elimination with support given, if necessary, through innovative financing measures to ensure elimination programmes are fully funded by 2020. In addition to further measures to improve access to vaccination and treatment, greater attention needs to be paid to access to affordable, high-quality diagnostics if testing is to reach the levels needed to achieve elimination goals. Simplified, decentralised models of care removing requirements for specialised prescribing will be required to reach those in need, together with sustained efforts to tackle stigma and discrimination. We identify key examples of the progress that has already been made in many countries throughout the world, demonstrating that sustained and coordinated efforts can be successful in achieving the WHO elimination goals.

Hepatitis B Surface Antigen Seroprevalence among Prevaccine and Vaccine Era Children in Bangladesh

Bangladesh introduced hepatitis B vaccine in a phased manner during 2003-2005 into the routine childhood vaccination schedule. This study was designed to evaluate the impact of the introduction of hepatitis B vaccine in Bangladesh by comparing hepatitis B surface antigen (HBsAg) prevalence among children born before and after vaccine introduction and to estimate the risk of vertical transmission of chronic hepatitis B virus (HBV) infection from mother to infant. We also evaluated the field sensitivity and specificity of an HBsAg point-of-care test strip. We selected a nationally representative sample of 2,100 prevaccine era and 2,100 vaccine era children. We collected a 5-mL blood sample from each child. One drop of blood was used to perform rapid HBsAg testing. If a child had a positive HBsAg test result with the rapid test, a blood sample was collected from the mother of the HBsAg-positive child and from the mothers of two subsequently enrolled HBsAg-negative children. All samples were tested for serologic markers of HBV infection using standard enzyme-linked immunosorbent assay. One (0.05%) child in the vaccine era group and 27 (1.2%; 95% confidence interval [CI]: 0.8-1.7%) children in the prevaccine era group were HBsAg positive. Mothers of HBsAg-positive children were more likely to be HBsAg positive than mothers of HBsAg-negative children (odds ratios = 4.7; 95% CI: 1.0-21.7%). Sensitivity of the HBsAg rapid test was 91.2% (95% CI: 76.6-98.1%) and specificity was 100% (95% CI: 99.9-100%). The study results suggest that even without a birth dose, the hepatitis B vaccine program in Bangladesh was highly effective in preventing chronic HBV infection among children.

Levels of regulatory B cells do not predict serological responses to hepatitis B vaccine

This study investigated the immunomodulatory influence of IL10 producing B regulatory cells, Bregs (CD19+CD24hiCD38hi) to standard Twinrix® vaccination. We also investigated HBsAg specific T-cell mediated IFN-γ responses to Twinrix® which in theory could provide effective immunity despite low anti-HBs titer. A total of 309 hepatitis B negative health care students and workers completed a standard Twinrix® vaccination schedule (0, 1 and 6 months). Depending on the vaccination response the participants were divided in to non-, low- and high responders according to anti-HBs titer (<10, <100 and >1000 mIU/mL respectively) two months after completed vaccination schedule. Blood samples from baseline and after vaccination from all non- and low-responders (23 participants) and the same number of high-responders were used for flow cytometric analyses of IL10 producing Bregs and T-cell mediated IFN-γ responses. A decrease in levels of IL10 producing Bregs was observed after vaccination in high responders compared to non- and low-responders. Compiling non-and low-responders against high-responders showed a lower T-cell mediated IFN-γ response at baseline in non-and low-responders when stimulated with Engerix® vaccine. In contrary no positive correlation between IL10 producing Bregs or IFN-γ positive T-cells and anti-HBs titer was observed. Hence this study cannot prove that levels of IL10 producing Bregs or IFN-γ positive T cell affect HBV vaccine response.

Characterization of hepatitis B virus in Amerindian children and mothers from Amazonas State, Colombia

BACKGROUND

Hepatitis B Virus (HBV) infection is a worldwide public health problem. In the 1980's a highly effective and safe vaccine against HBV was developed, although breakthrough infection still occasionally occurs because of the emergence of escape mutants. The aim of this study was to identify HBV genotypes and escape mutants in children and their mothers in Amerindian communities of the Amazonas State, Southern Colombia.

METHODS

Blood specimens collected from children and mothers belonging to 37 Amerindian communities in Amazonas state, were screened for HBsAg and anti-HBc using ELISA. The partial region containing the S ORF was amplified by nested PCR, and amplicons were sequenced. The phylogenetic analysis was performed using the MEGA 5.05 software.

RESULTS

Forty-six children (46/1275, 3.6%) and one hundred and seventy-seven mothers (177/572, 30.9%) were tested positive for the anti-HBc serological marker. Among them, 190 samples were tested for viral genome detection; 8.3% (2/31) serum samples obtained from children and 3.1% (5/159) from mothers were positive for the ORF S PCR. The predominant HBV genotype in the study population was F, subgenotype F1b; in addition, subgenotype F1a and genotype A were also characterized. Two HBV escape mutants were identified, G145R, reported worldwide, and W156*; this stop codon was identified in a child with occult HBV infection. Other mutations were found, L109R and G130E, located in critical positions of the HBsAg sequence.

CONCLUSIONS

This study aimed to characterize the HBV genotype F, subgenotypes F1b and F1a, and genotype A in Amerindian communities and for the first time escape mutants in Colombia. Further investigations are necessary to elucidate the frequency and the epidemiological impact of the escape mutants in the country.

Epidemiology of hepatitis B and the role of vaccination

Hepatitis B virus (HBV) is a major cause of morbidity and mortality with a disproportionate impact on Asia and Africa. Current guidelines recommend screening at-risk populations for chronic HBV infection so that diagnosed individuals can be linked to appropriate hepatitis care. The vast majority of infected individuals are undiagnosed and untreated, and are at risk of developing cirrhosis, liver failure, and hepatocellular carcinoma. In individuals who are not yet infected, the HBV vaccine is safe and highly effective at preventing disease transmission. Countries with successful vaccination programs have been able to dramatically reduce their HBV prevalence. A concerted effort to screen, treat, and vaccinate at-risk individuals has the potential to eliminate HBV as a public health threat by 2030.

Progress in vaccination towards hepatitis B control and elimination in the Region of the Americas

BACKGROUND

Over recent decades, the Region of the Americas has made significant progress towards hepatitis B elimination. We summarize the countries/territories' efforts in introducing and implementing hepatitis B (HB) vaccination and in evaluating its impact on HB virus seroprevalence.

METHODS

We collected information about HB vaccination schedules, coverage estimates, and year of vaccine introduction from countries/territories reporting to the Pan American Health Organization/World Health Organization (PAHO/WHO) through the WHO/UNICEF Joint Reporting Form on Immunization. We obtained additional information regarding countries/territories vaccination recommendations and strategies through communications with Expanded Program on Immunization (EPI) managers and national immunization survey reports. We identified vaccine impact studies conducted and published in the Americas.

RESULTS

As of October 2016, all 51 countries/territories have included infant HB vaccination in their official immunization schedule. Twenty countries, whose populations represent over 90% of the Region's births, have included nationwide newborn HB vaccination. We estimated at 89% and 75%, the regional three-dose series and the birth dose HB vaccination coverage, respectively, for 2015. The impact evaluations of infant HB immunization programs in the Region have shown substantial reductions in HB surface antigen (HBsAg) seroprevalence.

CONCLUSION

The achievements of vaccination programs in the Americas suggest that the elimination of perinatal and early childhood HB transmission could be feasible in the short-term. Moreover, the data gathered indicate that the Region may have already achieved the 2020 WHO goal for HB control.

Epidemiological, serological and molecular aspects of hepatitis B and C in children and teenagers of municipal daycare facilities schools and schools in the city of Santos

OBJECTIVE

To estimate the prevalence of the serological markers anti-HBc, HBsAg and anti-HBs of hepatitis B and anti-HCV of hepatitis C among children and teenagers enrolled at daycare facilities, kindergartens and municipal elementary education network in the city of Santos, São Paulo, Brazil.

METHODS

A cross-sectional study was carried out from June 28 to December 14, 2007, in which 4,680 finger-prick blood samples were collected from children and teenagers. A survey questionnaire was applied to their family members. The sample was dimensioned using the software Epi Info version 6 with expected frequency of 1%, acceptable error of 0.5% and confidence interval of 95%. The serological tests were performed using the ELISA technique. The molecular analysis was performed using the technique of polymerase chain reaction in House.

RESULTS

Age of the studied population ranged from 7 months to 18 years and 1 month. The general prevalence of anti-HBc reagent was 0.1%, HBsAg was 0.02% and anti-HCV was 0.02%.

CONCLUSIONS

In children, the general prevalence of serological markers for hepatitis B and C in the city of Santos was low when compared with literature data.

Compliance with birth dose of Hepatitis B vaccine in high endemic and hard to reach areas in the Colombian amazon: results from a vaccination survey

BACKGROUND

Hepatitis B vaccination was introduced into the Expanded Program of Immunization in Colombia in 1992, in response to WHO recommendations on hepatitis B immunization. Colombia is a low endemic country for Hepatitis B virus infection (HBV) but it has several high endemic areas like the Amazon basin where more than 70 % of adults had been infected. A cross- sectional study was carried out in three rural areas of the Colombian Amazon to evaluate compliance with the recommended schedule for hepatitis B vaccine in Colombian children (one monovalent dose given in the first 24 h after birth + 3 doses of a pentavalent containing Hepatitis B. (DPT + Hib + Hep B).

METHODS

A household survey was conducted in order to collect vaccination data from children aged from 6 months to <8 years. Vaccination status was related to sociodemographic data obtained from children caretakers.

RESULTS

Among 938 children above 6 months and < 8 years old studied, 79 % received a monovalent dose of hepatitis B vaccine, but only 30.7 % were vaccinated in the first 24 h after birth. This proportion did not increase by age or subsequent birth cohorts. Coverage with three doses of a DTP-Hib-HepB vaccine was 98 %, but most children did not receive them according to the recommended schedule. Being born in a health facility was the strongest predictor of receiving a timely birth dose.

CONCLUSIONS

This study suggests that more focused strategies on improving compliance with hepatitis B birth dose should be implemented in rural areas of the Amazon, if elimination of perinatal transmission of HBV is to be achieved. Increasing the proportion of newborns delivered at health facilities should be one of the priorities to reach that goal.

Status of hepatitis B infection - a decade after hepatitis B vaccination of susceptible Nicobarese, an indigenous tribe of Andaman & Nicobar (A&N) islands with high hepatitis B endemicity

BACKGROUND & OBJECTIVES

Andaman and Nicobar Islands of India, home to six primitive tribes, constituting about 10 per cent of the total population of these Islands have been detected with high endemicity of hepatitis B infection. During 2000, a total of 936 individuals ≤ 45 yr, negative for hepatitis B surface antigen (HBsAg) and antibody anti-HBs were vaccinated with three doses of a recombinant DNA hepatitis B vaccine in two villages of Car Nicobar Islands. The present study was undertaken to evaluate the impact of the hepatitis B vaccination with respect to the persistence of antibodies and incidence of new infections, prevalence of surface gene mutations among the Nicobarese community in the two villages ten years after hepatitis B vaccination.

METHODS

Follow up samples were collected from 211 individuals who had received three doses of vaccine ten years back and from a control group of 515 non-vaccinated individuals. The HBsAg, anti-HBs and anti-HBc assay results were compared among vaccinated and non-vaccinated groups. HBV DNA was extracted and sequenced from all the samples for detection of mutation. Genotyping and serotyping of the viruses were performed.

RESULTS

The results showed that 85.3 per cent of the vaccinated persons retained protective level of antibodies and among the non-vaccinated individuals, 54.2 per cent showed presence of anti-HBs indicating an exposure to the infection. The overall HBsAg positivity among the studies Nicobarese individuals was reduced to 7.4 per cent after 10 years of vaccination. Anti-HBc was positive in 60.6 and 57 per cent among the vaccinated and non-vaccinated individuals, respectively. Overall breakthrough infection of 8.5 per cent was detected among the vaccinated individuals. The predominant genotype and serotype circulating among these tribal populations were D and ayw3, respectively.

INTERPRETATION & CONCLUSIONS

The results of this study showed an overall reduction in the pool of HBsAg carriers because of the vaccination which helped in reducing the HBsAg carrier rate among the non-vaccinated also, probably due to an increase in herd immunity and reduction in the source of infection. Further studies need to be done to evaluate long term benefits of hepatitis B vaccination among these tribes.

Hepatitis B virus burden in developing countries

Hepatitis B virus (HBV) infection has shown an intermediate or high endemicity level in low-income countries over the last five decades. In recent years, however, the incidence of acute hepatitis B and the prevalence of hepatitis B surface antigen chronic carriers have decreased in several countries because of the HBV universal vaccination programs started in the nineties. Some countries, however, are still unable to implement these programs, particularly in their hyperendemic rural areas. The diffusion of HBV infection is still wide in several low-income countries where the prevention, management and treatment of HBV infection are a heavy burden for the governments and healthcare authorities. Of note, the information on the HBV epidemiology is scanty in numerous eastern European and Latin-American countries. The studies on molecular epidemiology performed in some countries provide an important contribution for a more comprehensive knowledge of HBV epidemiology, and phylogenetic studies provide information on the impact of recent and older migratory flows.

Hepatitis D virus and hepatitis B virus infection in Amerindian communities of the Amazonas state, Colombia

BACKGROUND

In Colombia, cases of Hepatitis D virus (HDV) infection have been officially described since 1985 mainly in Amerindian population from Sierra Nevada de Santa Marta (North Caribbean Coast), Uraba (North West), and Amazon (South East). The last official report of a clinical case of HDV infection in Colombia was registered in 2005.

OBJECTIVES

The aims of this study were to identify cases of HDV and/or Hepatitis B virus (HBV) infection in asymptomatic Amerindians from Amazonas state, South East Colombia, and to describe the circulating viral genotypes in this population.

STUDY DESIGN

The study population was recruited in 19 Amerindian communities in the Amazonas state. Individuals over 18 years old were screened by rapid test for Hepatitis B surface Antigen (HBsAg). Blood samples obtained from individuals positives for HBsAg in the rapid-test assay were analyzed for HBsAg, anti-HBc, anti-HDV IgM/IgG by ELISA. The detection of HBV DNA and HDV RNA was performed by PCR amplification. The viral genotype was determined by sequencing and phylogenetic analysis.

RESULTS

A total of 23/861 individuals were positive for HBsAg detection by rapid test. Serological and/or molecular markers of HDV infection were demonstrated in 43.5 % (10/23) of samples from Amerindians. The phylogenetic analysis demonstrated the exclusive circulation of HBV subgenotype F1b of and HDV 3 in this population.

CONCLUSIONS

A high frequency of HBV/HDV infection was found in Amerindian population from Amazonas State, Colombia (43.5 %, 10/23). Nine cases were identified in a population of 861 asymptomatic Amerindian individuals; one symptomatic case (with diagnosis of end-stage hepatic disease) was also identified in the study. The circulation of HDV 3 and HBV subgenotype F1b suggests a constant flow of these viral genotypes as a result of the interaction of the Amerindian populations from Amazon basin. Further studies are necessary to confirm whether HBV subgenotype F1b is the prevalent in the population from South East region in Colombia.

Discovery of a Novel Mutation (X8Del) Resulting in an 8-bp Deletion in the Hepatitis B Virus X Gene Associated with Occult Infection in Korean Vaccinated Individuals

Universal infantile hepatitis B virus (HBV) vaccination may lead to an increase in vaccine escape variants, which may pose a threat to the long-term success of massive vaccination. To determine the prevalence of occult infections in Korean vaccinated individuals, 87 vaccinated subjects were screened for the presence of HBV DNA using both the nested PCR protocol and the VERSANT HBV DNA 3.0 assay. The mutation patterns of variants were analyzed in full-length HBV genome sequences. Their HBsAg secretion and replication capacities were investigated using both in vitro transient transfection and in vivo hydrodynamic injection. The presence of HBV DNA was confirmed in 6 subjects (6.9%). All six variants had a common mutation type (X8Del) composed of an 8-bp deletion in the C-terminal region of the HBV X gene (HBxAg). Our in vitro and in vivo analyses using the full-length HBV genome indicated that the X8Del HBxAg variant reduced the secretion of HBsAg and HBV virions compared to the wild type. In conclusion, our data suggest that a novel mutation (X8Del) may contribute to occult HBV infection in Korean vaccinated individuals via a reduced secretion of HBsAg and virions, possibly by compromising HBxAg's transacting capacity.

Perfiles serológicos de hepatitis B en donantes de sangre con anti-HBc reactivos

<p><strong>Objetivo </strong>Determinar los perfiles serológicos para el virus de hepatitis B, en donantes de sangre anti-HBc reactivo y antígeno de superficie no reactivo, provenientes de cuatro ciudades del país<strong></strong></p><p><strong>Métodos</strong> Se realizó un estudio prospectivo transversal, durante un período de 17 meses, aplicando el perfil serológico completo de la hepatitis B, en muestras de donantes con anti-HBc reactivo y antígeno de superficie de hepatitis B no reactivo. Los resultados fueron analizados utilizando Microsoft^® Excel y Epiinfo V 3.5.1.</p><p><strong>Resultados </strong>Se encontró que el 75 % de los donantes reactivos para anti-HBc en los bancos de sangre, presentaban algún marcador adicional de exposición para el VHB; el 1,3 % de los donantes presentaban marcadores serológicos de infección crónica por hepatitis B y un caso que resultó reactivo solamente para antígeno de superficie de hepatitis B. Se halló perfil de vacunación en el 6,1 % de donantes, que fueron reactivos solamente para anticuerpo contra antígeno de superficie.</p><p><strong>Conclusiones. </strong>Se ratifica la importancia de la tamización de anti-HBc, a los donantes de sangre.</p>

Association of preS/S Mutations with Occult Hepatitis B Virus (HBV) Infection in South Korea: Transmission Potential of Distinct Occult HBV Variants

Occult hepatitis B virus infection (HBV) is characterized by HBV DNA positivity but HBV surface antigen (HBsAg) negativity. Occult HBV infection is associated with a risk of HBV transmission through blood transfusion, hemodialysis, and liver transplantation. Furthermore, occult HBV infection contributes to the development of cirrhosis and hepatocellular carcinoma. We recently reported the characteristic molecular features of mutations in the preS/S regions among Korean individuals with occult infections caused by HBV genotype C2; the variants of preS and S related to severe liver diseases among chronically infected patients were also responsible for the majority of HBV occult infections. We also reported that HBsAg variants from occult-infected Korean individuals exhibit lower HBsAg secretion capacity but not reduced HBV DNA levels. In addition, these variants exhibit increased ROS-inducing capacity compared with the wild-type strain, linking HBV occult infections to liver cell damage. Taken together, our previous reports suggest the transmission potential of distinct HBV occult infection-related variants in South Korea.

Prevalence of National Responsiveness to HBV Vaccine After 22 Years of Iranian Expanded Program on Immunization (EPI): A Systematic Review and Meta-Analysis Study

CONTEXT

Hepatitis B Virus expanded program on immunization (EPI) started on 1993 in Iran. Most surveys have assessed the level of response to vaccine by measuring the titers of anti-HBs. This meta- analysis aimed to summarize the Iranian published data on the rate of vaccine-responders versus non-responders. Moreover, the impact of variables such as age, gender, type of vaccine, etc. on the levels of responsiveness was evaluated.

EVIDENCE ACQUISITION

All published papers on this topic in Iranian and international journals with affiliation of "Iran" were reviewed using standard keywords up to 2014. We included our study to healthy participants with no previous HBV infection and who had already received a complete course of HB vaccine. The estimated prevalence and 95% confidence intervals in 28 eligible articles for HBV vaccine responders (anti-HBs > 10 IU/mL) and non-responders (10 <) were analyzed by random effect method due to between-study heterogeneity.

RESULTS

The age of subjects was between 6 months and 15 years old. Overall, 5991 (51.5%) were male and 4571 (48.5%) females. Overall, 80% were responders to vaccine versus 20% nonresponders. With increase in age, the number of responders to vaccine decreased significantly (P = 0.001). There was no strong difference between responders versus nonresponders to vaccine for gender, types of vaccine, ethnicity and living area.

CONCLUSIONS

The results arose from this meta-analysis highlighted the safety of vaccine and its effectiveness in stimulating immune response of vaccines, despite being different in generation, manufacturers and types. Moreover, there was no substantial difference between Iranian and other international investigations in the rate of nonresponsiveness to HBV vaccine.

Improving hepatitis B vaccine timely birth dose coverage: lessons from five demonstration projects in China, 2005-2009

BACKGROUND

Delivery of a timely (within 24h) hepatitis B vaccine birth dose (TBD) is essential to prevent the long-term complications of hepatitis B virus (HBV) infection. China made substantial progress in hepatitis B immunization coverage, however, in 2004, TBD coverage was lower in Western, poorer provinces.

METHODS

We reviewed five demonstration projects for the promotion of TBD in rural counties in Qinghai, Gansu and Ningxia. Interventions consisted of (1) work to increase TBD coverage in hospitals, including training of health-care workers, (2) information, education and communication [IEC] with the population and (3) micro-plans to deliver TBD for home births. We evaluated outcome through measuring TBD coverage for home and hospital births.

RESULTS

These projects were implemented in the context of national efforts to promote institutional deliveries that lead to increases ranging from 10% to 17% to reach 43-97% proportion of institutional births at the end of the projects. Among institutional births, TBD coverage increased by 2% to 13% to reach post implementation coverage ranging from 98% to 100%. Among home births, TBD coverage increased by 7% to 56% to reach post implementation coverage ranging from 29% to 88%. Overall, TBD coverage increased by 4% to 36% to reach post implementation coverage ranging from 82% to 88%.

CONCLUSIONS

Demonstration projects based on combined interventions increased TBD coverage. Increases in institutional births amplified the results obtained. Use of standardized indicators for such projects would facilitate evaluation and identify intervention components that are most effective.

Hepatitis B virus: Where do we stand and what is the next step for eradication?

Hepatitis B (HB) virus (HBV) infection, which causes liver cirrhosis and hepatocellular carcinoma, is endemic worldwide. Hepatitis B vaccines became commercially available in the 1980s. The World Health Organization recommended the integration of the HB vaccine into the national immunisation programs in all countries. HBV prevention strategies are classified into three groups: (1) universal vaccination alone; (2) universal vaccination with screening of pregnant women plus HB immune globulin (HBIG) at birth; and (3) selective vaccination with screening of pregnant women plus HBIG at birth. Most low-income countries have adopted universal vaccine programs without screening of pregnant women. However, HB vaccines are not widely used in low-income countries. The Global Alliance for Vaccine and Immunization was launched in 2000, and by 2012, the global coverage of a three-dose HB vaccine had increased to 79%. The next challenges are to further increase the coverage rate, close the gap between recommendations and routine practices, approach high-risk individuals, screen and treat chronically infected individuals, and prevent breakthrough infections. To eradicate HBV infections, strenuous efforts are required to overcome socioeconomic barriers to the HB vaccine; this task is expected to take several decades to complete.

Socio-demographic and behavioral determinants of hepatitis B vaccination and infection in pregnant women on Mayotte Island, Indian Ocean

BACKGROUND

Socio-demographic and behavioral determinants of Hepatitis B virus (HBV) vaccination and infection among pregnant women (PW) of Mayotte Island (Indian Ocean) are not well understood.

METHODS

Six hundred and seventy-one pregnant women presenting to public antenatal clinics on Mayotte Island were included between September 15, 2008 and September 27, 2009. Socio-demographics, sexual risk behavior characteristics, and data for HBV biomarkers were collected. Logistic regression was undertaken to study determinants of HBV vaccination and factors associated with the risk of HBV infection were assessed using a survival method adapted to interval-censored data. Due to missing data for HBV biomarkers, data were analyzed using multiple imputation (MI).

RESULTS

Past or recent HBV infection was observed for 35.5% (95% confidence interval (CI): 30.4-40.8) of PW and 18.6% (95% CI: 14.7-23.2) had evidence of HBV vaccination. PW with unemployed and education qualification (adjusted odds ratio (aOR) 2.65, 95% CI 1.52-4.60) and student status (aOR 4.79, 95% CI 1.63-4.07) were better vaccinated against HBV, compared to those without employment and education. Being born on Comoros was associated with a 63% reduction in HBV vaccination (aOR 0.37, 95% CI 0.21-0.65), compared to be born in Mayotte/France. Women with a history of sexually-transmitted infections in the last 5 years had an increased risk of HBV infection (adjusted hazard ratio (aHR) 3.10, 95% CI: 1.13-8.50), whereas those who sometimes used condoms had a 60% reduced risk (aHR=0.40, 95% CI: 0.23-0.69).

CONCLUSIONS

Socio-demographic factors were identified for HBV vaccination, while behavioral factors were observed for HBV infection. These results could help to determine priorities for intervention.

Epidemiology and molecular characterization of hepatitis B virus infection in isolated villages in the Western Brazilian Amazon

Individuals from three isolated, rural communities in the western Brazilian Amazon were evaluated for serological markers of hepatitis B virus (HBV) infection, HBV genotype, and the presence of risk factors for infection and transmission. Of the 225 individuals studied, 79.1% had serological evidence of HBV infection; 10.2% individuals were chronic carriers for HBV surface antigen (HBsAg-positive). Analysis of risk factors indicates that HBV is transmitted mainly horizontally within the family from a chronic "active" carrier for hepatitis B "e" antigen (HBeAg-positive), though a strong possibility of vertical transmission remains. The predominance of HBV genotype F, with a higher genomic similarity between the isolates, indicated a relatively recent introduction of HBV, from a common source, to the area. This study sheds light on the HBV epidemiology in the Brazilian Amazon region and highlights the need for greater emphasis on HBV control and immunization programs.

Prevalence of hepatitis B virus infection and carriage after nineteen years of vaccination program in the Western Brazilian Amazon

INTRODUCTION

Reductions in the prevalence of hepatitis B virus (HBV) infection and carriage, decreases in liver cancer incidence, and changes in patterns of liver dysfunctions are described after hepatitis B vaccination.

METHODS

We conducted a population-based seroprevalence study aimed at estimating the HBV prevalence and risk of infection in the rural area of Lábrea following nineteen years of HBV vaccination.

RESULTS

Half of the subjects showed total anti-HBc of 52.1% (95% CI 49.6-54.7). The HBsAg prevalence was 6.2% (95% CI 5.1-7.6). Multivariate analysis showed an inverse association between HBV infection and vaccination (OR 0.62; 95% CI 0.44-0.87). HBsAg remained independently associated with past hepatitis (OR 2.44; 95% CI 1.52-3.89) and inversely to vaccination (OR 0.43; 95% CI 0.27-0.69). The prevalence of HBeAg among HBsAg-positive individuals was 20.4% (95% CI 12.8-30.1), with the positive subjects having a median age of 11 years (1-46) p=0.0003.

CONCLUSIONS

We demonstrate that HBV infection is still an important public health issue and that HBV vaccination could have had better impact on HBV epidemiology. If we extrapolate these findings to other rural areas in the Brazilian Amazon, we can predict that the sources of chronic infected patients remain a challenge. Future studies are needed regarding clinical aspects, molecular epidemiology, surveillance of acute cases, and risk groups.

Hepatitis B and Hepatitis C Infection Biomarkers and TP53 Mutations in Hepatocellular Carcinomas from Colombia

Hepatocellular Carcinoma (HCC) is a leading cause of cancer-related death worldwide. Globally, the most important HCC risk factors are Hepatitis B Virus (HBV) and/or Hepatitis C Virus (HCV), chronic alcoholism, and dietary exposure to aflatoxins. We have described the epidemiological pattern of 202 HCC samples obtained from Colombian patients. Additionally we investigated HBV/HCV infections and TP53 mutations in 49 of these HCC cases. HBV biomarkers were detected in 58.1% of the cases; HBV genotypes F and D were characterized in three of the samples. The HCV biomarker was detected in 37% of the samples while HBV/HCV coinfection was found in 19.2%. Among TP53 mutations, 10.5% occur at the common aflatoxin mutation hotspot, codon 249. No data regarding chronic alcoholism was available from the cases. In conclusion, in this first study of HCC and biomarkers in a Colombian population, the main HCC risk factor was HBV infection.

Etiology and Viral Genotype in Patients with End-Stage Liver Diseases admitted to a Hepatology Unit in Colombia

Hepatitis B virus (HBV) and hepatitis C virus (HCV) infections are the principal risk factor associated to end-stage liver diseases in the world. A study was carried out on end-stage liver disease cases admitted to an important hepatology unit in Medellin, the second largest city in Colombia. From 131 patients recruited in this prospective study, 71% of cases were diagnosed as cirrhosis, 12.2% as HCC, and 16.8% as cirrhosis and HCC. Regarding the risk factors of these patients, alcohol consumption was the most frequent (37.4%), followed by viral etiology (17.6%). Blood and/or hepatic tissue samples from patients with serological markers for HCV or HBV infection were characterized; on the basis of the phylogenetic analysis of HCV 5' UTR and HBV S gene, isolates belonged to HCV/1 and HBV/F3, respectively. These results confirm the presence of strains associated with poor clinical outcome, in patients with liver disease in Colombia; additionally, HBV basal core promoter double mutant was identified in HCC cases. Here we show the first study of cirrhosis and/or HCC in Colombian and HBV and HCV molecular characterization of these patients. Viral aetiology was not the main risk factor in this cohort but alcohol consumption.