Long-term protection against HBV chronic carriage of Gambian adolescents vaccinated in infancy and immune response in HBV booster trial in adolescence

Evaluation of Immune Characteristics and Factors Associated with Immune Response following Hepatitis B Vaccination among Ghanaian Adolescents

Background

WHO recommends HBV-negative babies in high-prevalence (8%) countries receive anti-HBV vaccination. Ghana initiated mass immunization in 2002, but concerns remain about vaccine effectiveness and long-term protection. We evaluated immune characteristics and factors following hepatitis B vaccination among Ghanaian adolescents who received HBV vaccines.

Methods

In this longitudinal cross-sectional study, 74 participants were enrolled from the Kumasi Metropolis, Ghana. Sociodemographic and lifestyle characteristics of participants were obtained using a questionnaire. Blood samples were obtained before and after booster administration for anti-HBsAg, IL-6, and IL-10 estimations using ELISA kit (Shanghai Chemical Ltd., China). Anti-HBsAg titers ≥10 mIU/ml were considered protective. Statistical analyses were done using SPSS version 26.0 and R programming language, p < 0.05 was considered statistically significant.

Results

We found 100% seroconversion rate, with 25.7% seroprotection rate (anti-HBsAg >10 mIU/ml). Gender (p=0.009), age (p=0.001), and exercising (p=0.044) were significantly associated with seroprotection. Following booster administration, 59.4% were hyporesponders (10 ≤ anti-HBsAg titre ≤99 mIU/ml) whilst 40.6% were good responders (anti-HBsAg titre ≥100 mIU/ml). Exercise (p=0.034) was significantly associated with immune response after booster administration. Moreover, we reported significant positive correlation between cytokines [IL-6 (r = 0.817, p < 0.001) and IL-10 (r = 0.928, p < 0.001)] and anti-HBsAg titre.

Conclusion

Approximately two thirds of adolescents vaccinated at birth lack protective levels of antibodies against hepatitis B virus. Booster vaccines could aid in mounting protective levels of anti-HBsAg. Physical exercise was negatively associated with immune response to hepatitis B vaccinations.

A systematic review reveals that African children of 15-17 years demonstrate low hepatitis B vaccine seroprotection rates

Childhood HBV immunization remains globally fundamental to the elimination of hepatitis B virus (HBV). However, monitoring proportions of HBV vaccine seroprotection and their determinants among African Pediatric recipients is crucial. This study sought to verify extent of immune protection accorded by the HBV vaccine in African children of up to 17 years of age by pooling the prevalence of seroprotection reported by primary studies conducted in the Northern, Western, and Southern African regions. We included 19 eligible articles out of the 197 initially downloaded, published from 1999 to 2021 from African Journals Online (AJOL), EMBASE, Scopus, and PubMed. The study protocol was registered with the International Prospective Register of Systematic Reviews (PROSPERO), University of York Centre for Reviews and Dissemination, under the registration number CRD42022361277. Significantly higher (p < 0.0001) proportion of HBV vaccine seroprotection (69.07%) was found among children under 15 years of age than children 15-17 years (32.368%), 95% CI [34.2454-39.0847%]. Whereas successful integration of the HBV vaccine on the extended programs on immunizations (EPI) has been a major achievement in the reduction of HBV infection in Africa, markedly reduced HBV vaccine seroprotection is persistently demonstrated among adolescent children 15-17 years of age. Future studies are required to clarify the need for booster dose vaccination in most at risk populations and age groups.

Immune response to hepatitis B vaccine following complete immunization of children attending two regional hospitals in the Southwest region of Cameroon: a cross sectional study

BACKGROUND

Hepatitis B virus (HBV) infection despite being a vaccine preventable disease remains a global public health problem. In Cameroon, the hepatitis B vaccine was introduced in the expanded program on immunisation in 2005, but there has been limited evaluation of the HBV surface antibody response post vaccination.

OBJECTIVE

We investigated the immune response to hepatitis B vaccine in infants who received the DPT-Hep B-Hib vaccine, and we assessed HBsAg carriage in non-responders. We also investigated factors associated with non-response or poor response.

METHODS

Using a hospital based cross sectional design and a structured questionnaire over a four-month period (January to April 2019), we collected data to determine factors associated with hepatitis B surface antibody (anti-HBs) response from infants aged 6 to 9 months attending infant welfare clinics (IWC) at the Buea and Limbe regional hospitals. We collected venous blood and measured anti-HBs titres using a quantitative Foresight® ELISA. We entered and analysed data using EpiData version 3.1 and SPSS version 25 respectively.

RESULTS

Of the 161 infants enrolled, 159 (98.8%) developed anti-HBs antibodies. Of these 159, 157 (97.5%) and 117 (72.7%) developed ≥ 10.0 mIU/ml (seroprotection) and ≥ 100.0 mIU/ml anti-HBs titres respectively. Being younger (6 months old) was associated with seroprotection (Cramer V = 0.322, p = 0.001). Spearman rho's relational analysis showed that immunity against HBV reduced as the duration since the last dose increased (r = -0.172; P = 0.029). However, a Firth logistic regression showed no significant association of factors with inadequate immunity. All 12 (7.5%) infants exposed to HBV at birth, received the hepatitis B vaccine at birth, including four who received HBIG, and all were protected. Four infants (2.5%) had anti-HBs titres < 10.0 mIU/mL (non-responders) but had no peculiarity.

CONCLUSION

The seroprotective rate following hepatitis B vaccination of infants is high even in exposed infants. Our study suggests that Cameroon's HBV vaccine in the Expanded Program on Immunisation (EPI) is effective against HBV, although we could not account for the 2.5% non-response rate. Large scale studies are needed to further explore non-response to the vaccine.

Prevalence of Hepatitis B Vaccination Coverage and Serologic Evidence of Immunity Among US-Born Children and Adolescents From 1999 to 2016

IMPORTANCE

The World Health Assembly has called for the elimination of hepatitis B and C by 2030. As hepatitis B has no cure, the US strategy to eliminate hepatitis B has focused on prevention through vaccination. However, there are limited data on the trend in vaccine-associated immunity since the US implementation of universal infant hepatitis B vaccination.

OBJECTIVE

To compare self-reported hepatitis B vaccination coverage among children and adolescents with serologic evidence of immunity and infection in the US from 1999 to 2016.

DESIGN, SETTING, AND PARTICIPANTS

This population-based cross-sectional study used data from the National Health and Nutrition Examination Survey (NHANES) from 1999 to 2016. US-born persons aged 2 to 18 years without missing hepatitis B serologic test results and with reported vaccination history were included. Data were analyzed from September 2017 to June 2018.

MAIN OUTCOMES AND MEASURES

The proportion of participants who reported complete vaccination for hepatitis B and who had positive serologic test results indicating immunity.

RESULTS

Of 21 873 children and adolescents, 51.2%% were male, and the mean (SD) age was 10.6 (4.6) years. The survey reported that hepatitis B vaccination coverage increased significantly from 1999 to 2016 (from 62.6% [95% CI, 58.6%-66.4%] to 86.3% [95% CI, 82.9%-89.2%]; P < .001). Vaccine-associated immunity also increased from 1999 to 2016 among children aged 2 to 5 years (from 60.7% [95% CI, 48.8%-71.4%] to 65.2% [95% CI, 57.4%-72.3%]; P = .001) but decreased among children aged 6 to 10 years (from 64.6% [95% CI, 57.7%-70.9%] to 46.5% [95% CI, 39.1%-54.0%]; P < .001), adolescents aged 11 to 13 years (from 68.8% [95% CI, 58.1%-77.8%] to 26.2% [95% CI, 18.6%-35.5%]; P < .001), and adolescents aged 14 to 18 years (from 68.5% [95% CI, 62.9%-73.6%] to 15.6% [95% CI, 12.2%-19.8%]; P < .001). By birth year, serologic evidence of vaccine-associated immunity significantly decreased in the 1994-2003 NHANES birth cohort but not among those born between 1988 and 1993. Non-US-born children and adolescents did not show the same decreasing trend in immunity.

CONCLUSIONS AND RELEVANCE

In this cross-sectional study, decreasing hepatitis B immunity was observed among US-born children and adolescents in the 1994-2003 NHANES birth cohort despite increasing rates of hepatitis B vaccination coverage. These findings suggest a possible need for surveillance and a booster vaccine dose for hepatitis B as those without serologic evidence of immunity become young adults and may engage in behaviors associated with an increased risk for infection.

No evidence of occult HBV infection in population born after mass vaccination

Despite access to efficient hepatitis B virus (HBV) vaccine and universal immunization schedules, HBV infection remains a global health concern. HBV infection has decreased by this program. Nevertheless, breakthrough infections occur due to generation of occult HBV infection (OBI) and surface gene mutants in the immunized population. We aimed to determine the presence of OBI in a population born after initiation of nationwide HBV vaccination in Tehran, Iran. A HBV mass vaccination schedule was launched in Iran in 1993. For this study, we enrolled 1120 cases younger than 24 years. ELISA was applied to evaluate the presence of HBsAg, anti-HBs and anti-HBc. HBV-DNA presence was determined in all HBsAg-negative cases using nested polymerase chain reaction. The prevalence of HBsAg, anti-HBc and anti-HBs was 0.1, 0.54 and 39.9% respectively. Out of 6 anti-HBc-positive individuals, 4 cases also had anti-HBs. One case revealed HBsAg co-existence and the other one showed isolated anti-HBc. HBV-DNA was not detected in HBsAg-negative specimens. A very low prevalence of HBsAg and isolated anti-HBc was observed and no occult HBV infection was detected. It seems that evasion mutants are not a potential threat for HBV universal immunization efficacy in the vaccinated population.

Hepatitis B and pertussis antibodies in 4- to 5-year-old children previously vaccinated with different hexavalent vaccines

In randomized active-comparator controlled studies, DTaP5-HB-IPV-Hib showed comparable immunogenicity and safety to other licensed vaccines. This study assessed persistence of anti-hepatitis B surface antigen (HBs) and anti-pertussis antibodies, when children were 4 to 5 years of age, 3 to 4 years after initial infant/toddler hexavalent vaccination. This was an extension of 2 European studies in which infants/toddlers received either DTaP5-HB-IPV-Hib or DTaP3-HB-IPV/Hib on a 2 + 1 or 3 + 1 schedule. Primary endpoints included percentages with anti-HBs ≥10 mIU/mL, and anti-pertussis toxin (PT), anti-filamentous hemagglutinin (FHA), anti-pertactin (PRN), and anti-fimbriae types 2 & 3 (FIM) greater than or equal to the lower limit of quantitation (LLOQ). One month after 2 + 1 or 3 + 1 dosing, nearly all toddlers had anti-HBs ≥10 mIU/mL, and responded to the received pertussis antigens. Approximately 3 to 4 years later, 65.8%-70.2% in the DTaP5-HB-IPV-Hib and 82.0%-83.7% in the DTaP3-HB-IPV/Hib groups, respectively, had anti-HBs ≥10 mIU/mL. Percentages of children with pertussis antibodies above LLOQ after 2 + 1 dosing were 58.4% and 41.5% (anti-PT), 80.9% and 88.3% (anti-FHA), 66.1% and 72.6% (anti-PRN), and 94.4% and 3.3% (anti-FIM), in the DTaP5-HB-IPV-Hib and DTaP3-HB-IPV/Hib groups, respectively. This study demonstrated, as expected, waning of hepatitis B and pertussis antibodies during the 3 to 4 years after completion of a 3 + 1 or 2 + 1 hexavalent vaccination schedule. Nonetheless, anti-HBs levels ≥10 IU/mL and detectable antibodies against acellular pertussis antigens persisted in most study participants. The implications of these findings for the long-term prevention of hepatitis B and pertussis are further discussed.

Evaluation of antibody persistence after a four-dose primary hepatitis B vaccination and anamnestic immune response in children under 6 years

Introduction. Tunisia is an intermediate hepatitis B virus (HBV) endemic country. The vaccination against hepatitis B was introduced in 1995 including four doses with a first dose administrated at birth. Decreasing the level of antibodies against hepatitis B surface antigen (anti-HBs) over time can be alarming. This study was conducted to explore the anti-HBV immune response among children under 6 years old, vaccinated according to the national vaccination schedule, by evaluating the immunological response to primary vaccination and by exploring the anamnestic immune response to a booster dose.Methods. We conducted a cross-sectional prospective study from June 2016 to June 2017 (n=180), based on voluntary participation. Children were recruited from the public pediatric ward sectors in Sahloul University Hospital of Sousse in Central Tunisia. An anti-HB titre was determined based on electro-chemiluminescence micro-particle immunoassay (ECLIA), using Elecsys Anti-HBs II kit, Roche.Results. Mean age at the time of enrollment in the study was 33±14.8 months. The seroprotection rate was 77.2 %. The anti-HB titre differed significantly between the different age groups (P=0.002). The predicting variable for having no seroprotective antibody level was older age. Children with anti-HB levels <10 IU l^{- 1} were offered an additional dose of HBV vaccine. Anamnestic response 1 month after the challenge dose was observed in 100 % of subjects. The probability of developing a high antibody response, following the booster dose increased in conjunction with an increased pre-booster antibody level.Conclusion. The response to a booster dose suggests the persistence of immune memory in almost all vaccinated individuals. Although a booster dose increases substantially anti-HB titre, the clinical relevance of such an increase remains unknown.

Analysis of the in vitro replication phenotype of African hepatitis B virus (HBV) genotypes and subgenotypes present in Australia identifies marked differences in DNA and protein expression

Hepatitis B virus infection in Africa is characterised by distinct genotypes with observed differences in natural history and clinical outcomes. Replication-competent cDNA clones of African genotypes were generated from patient-derived sequences identified in African children with chronic hepatitis B infection living in Australia: A1 (wild-type and basal core promotor (BCP) mutant), D2, D6, and E, comparing the replication phenotype to an established D3 cDNA clone in a transient transfection cell culture model. All clones replicated efficiently although less than the European D3 reference clone, and demonstrated marked differences in replication capacity, highest for subgenotypes A1 and D2. The BCP mutation increased the replication levels of the A1 subgenotype compared to wild-type. Intracellular and secreted surface antigen and HBeAg protein expression also varied across genotypes. We observed differences in functional activity in the upstream regulatory region across the genotypes that may contribute to the replication and protein differences observed.

Long-term persistency of hepatitis B immunity: an observational cross-sectional study on medical students and resident doctors

Hepatitis B virus (HBV) is a main cause of chronic and acute hepatitis. Healthcare workers (HCWs), including medical students and resident doctors, have an occupational risk of HBV infection.

The study aimed to evaluate the long-term persistence of protective anti-HBs antibody levels in healthcare students and resident doctors at risk for occupational exposure to HBV at 15 years after primary vaccination course. Further objective was to evaluate the anamnestic response observed in non-seroprotected subjects receiving a booster dose.

Data were collected from the clinical documentation filled in during the occupational medical check of medical students and resident doctors undergoing Occupational Health Surveillance by the University of Ferrara.

Of the 621 included individuals, 27.7% had an anti-HBs concentration < 10 mIU/mL. Subjects vaccinated during infancy had more frequently a concentration < 10 mIU/mL than those vaccinated during adolescence (42.7% vs 6.9%; p-value < 0.001). Multivariate analysis confirmed the statistical significance of the vaccination age. 94 subjects who had an anti-HBs concentration < 10 mIU/mL received a booster dose. The proportion of subjects who had an anamnestic response was higher in those vaccinated in infancy rather than during adolescence (94.1% vs 77.8% respectively).

These findings suggest that the anti-HBs concentration decreases below 10 mIU/mL more frequently in subjects vaccinated during infancy. Immunological memory seems to persist after the decline of the anti-HB titer, as observed in response to a booster dose. In conclusion, vaccinated subjects at increased risk of HBV infection should be monitored and a booster dose administered if anti-HBs titer is below 10 mIU/mL.

Hepatitis B virus sero-prevalence amongst pregnant women in the Gambia

BACKGROUND

Infection with Hepatitis B virus (HBV) is a serious public health problem worldwide, with over 360 million carriers. Sixty million of these are resident in Sub-saharan Africa. Hepatitis B infection is the cause of Hepatocellular carcinoma (HCC), which is the second commonest cause of death from cancers among women in The Gambia. Vertical transmission is the commonest route of spread of Hepatitis B Virus in many endemic areas. The main aim of the study was to determine the sero-prevalence of Hepatitis B surface antigen (HBsAg) among pregnant women attending antenatal clinic at the Edward Francis Small Teaching Hospital, Banjul, The Gambia.

METHODS

Four hundred and twenty six pregnant women were recruited from our antenatal clinics and tested for HBsAg. Serum Hepatitis B surface antigen (HBsAg) was tested using commercial rapid diagnostic Elisa kits at the point of care.

RESULTS

A prevalence rate of 9.20% among all pregnant women studied was found. Women who were likely to have been vaccinated had a prevalence rate of 2.30% whiles those unlikely to have been vaccinated had a prevalence of 13.71%. There was a statistically significant difference between those likely to have been vaccinated and those unlikely to have been vaccinated.

CONCLUSION

The prevalence of hepatitis B infection is very high among pregnant women at EFSTH as in the high endemic zone that is more than 8%. However the prevalence rate is lower than the national average of 15%. The prevalence is of moderate endemicity among the women who likely received vaccination during childhood. More interventions during pregnancy need to be undertaken if more successes are to be registered.

Long-term impact of infant immunization on hepatitis B prevalence: a systematic review and meta-analysis

OBJECTIVE

To conduct a systematic review and meta-analysis of the long-term impact of infant vaccination on the prevalence of hepatitis B virus (HBV) infection at the population level.

METHODS

We searched online databases for articles reporting comparisons between population cohorts aged ≥ 15 years who were exposed or unexposed to infant HBV immunization programmes. We categorized programmes as universal or targeted to infants whose mothers were positive for hepatitis B surface antigen (HBsAg). We included studies reporting prevalence of hepatitis B core antibody (HBcAb), HBsAg, or both. We evaluated the quality of the study methods and estimated the relative reduction in the prevalence of infection.

FINDINGS

Of 26 studies that met the inclusion criteria, most were from China (20 studies). The prevalence of HBV infection in unvaccinated and universally vaccinated cohorts ranged from 0.6% (116 of 20 305 people) to 16.3% (60/367) and from 0.3% (1/300) to 8.5% (73/857), respectively. Comparing cohorts with universal vaccination to those without vaccination, relative prevalences were 0.24 (95% confidence interval, CI: 0.16-0.35) for HBsAg and 0.23 (95% CI: 0.17-0.32) for HBcAb. For populations with targeted vaccination, relative prevalences were 0.32 (95% CI: 0.24-0.43) and 0.33 (95% CI: 0.23-0.45), respectively.

CONCLUSION

The residual burden of infection in cohorts offered vaccination suggests that longer-term evaluations of vaccination coverage, timeliness and other aspects of programme quality are needed. As HBV-vaccinated infant cohorts reach adulthood, ongoing analysis of prevalence in adolescents and young adults will ensure that elimination efforts are on track.

Molecular characterization of hepatitis B virus (HBV) in African children living in Australia identifies genotypes and variants associated with poor clinical outcome

Migration from sub-Saharan Africa is contributing to the rising incidence of chronic hepatitis B (CHB) infection and its complications in Australia. African CHB is associated with unique genotypes, such as E and A1, which are associated with reduced vaccine efficacy and early-onset hepatocellular carcinoma, respectively, although the prevalence of these genotypes outside Africa is poorly described. Treatment-naïve children of African origin with CHB were recruited at the Royal Children's Hospital Melbourne. Population-based sequencing of the complete HBV genome, or the clinically relevant basal core promoter (BCP)/precore (PC) region, was performed, and the HBV genotype/subgenotype assigned by phylogenetic analysis. HBV was characterized in serum from 67 children, median age 12.5 years. HBV genotype E was most frequent (70 %), with genotype D [25 %; subgenotypes D6 (formerly D7)/D3/D2)] and subgenotype A1 (5 %) also being identified. Despite their young age, over 50 % of the children were HBeAg-negative and had seroconverted to anti-HBe, with this being associated with canonical BCP/PC mutations in the majority of cases. The profile of HBV in African children living in Australia was characterized by early HBeAg seroconversion and infection with HBV variants associated with poor clinical outcome, as well as genotypes previously associated with reduced vaccine efficacy or rapid progression to liver cancer. These findings have important ramifications for patient monitoring and treatment guidelines in the Australian paediatric setting.

Hepatitis B virus surface antigen and antibody markers in children at a major paediatric hospital after the pentavalent DTP-HBV-Hib vaccination

OBJECTIVES

The knowledge about outcomes of infant vaccination against HBV infections using the DPT-HepB-Hib vaccine in Ghana is limited. This study therefore investigated the levels of immunity to HBV among children who received the DPT-HepB-Hib vaccine and HBsAg carriage in non-responders. Correlates for non-response or poor response were also investigated.

METHODS

Cross-sectional study. A major paediatric hospital in Accra. Four hundred and twenty four children between the ages of 5 to 32 months who had completed the full vaccination schedule for the DPT-HepB-Hib vaccine.

RESULTS

Of the 424 children, 358 (84.4%) developed anti-HBs while 340 (80.2%) developed ≥10 mIU/ml anti-HBs (sero-protection) and 3 had HBsAg. A binary logistic regression analysis showed that younger children were associated with sero-conversion (p=.022) and sero-protection (p=.021). For anti-HBs titres ≥100 mIU/ml age was a weaker but significant contributor (p=.041), as compared to the number of vaccines from different manufacturers the child used (p=.028). The mean age of those who used a single type of vaccine was higher (14.75 ± 6.056 months; n=268) than those who used vaccines from two or more manufacturers (11.96 ± 4.645 months; n=156), p= <.001 (CI: -3.897 - 1.688), an indication that efforts to procure vaccine from same source when it was initially introduced are waning.

CONCLUSIONS

There is still a residual possibility of infection with HBV in spite of infant vaccination. In the light of possible loss of anamnestic response over time, there is the need to consider a birth dose for HBV vaccination for all neonates or booster dose for infants who may not have received the vaccine at birth. Using vaccines from a single manufacturer is recommended.

FUNDING

None declared.

Strategies for prevention of gastrointestinal cancers in developing countries: a systematic review

Background

Gastrointestinal cancers account for one third of total cancer incidence and mortality in developing countries. To date, there is no systematic synthesis of evidence regarding strategies to prevent gastrointestinal cancers in developing countries. We aimed to provide a systematic overview of studies evaluating strategies for prevention or early detection of the three most common gastrointestinal cancers (gastric, liver and colorectal cancer) in developing countries.

Methods

We searched MEDLINE, Web of Science and WHO Global Index Medicus databases for relevant articles published until October 2016 using combinations of the search terms “gastrointestinal”, “digestive system”, “gastric”, “liver”, “colorectal”, “cancer”, “prevention”, “early detection” and “developing country” (including names).

Results

Overall, 73 articles met the inclusion criteria, providing information on short– and long–term outcomes (up to 30 years) from various intervention studies (∼45% randomized). Trials on hepatitis B vaccination consistently showed vaccine efficacy over time and indicated long–term preventive effects on liver cancer incidence that start to become measurable at the population level. Studies on anti–H. pylori treatment suggested a reduction in gastric cancer incidence reaching statistical significance after long–term follow–up, while evidence regarding a preventive effect in persons with precancerous lesions is still inconclusive. The studies regarding colorectal cancer focused on early detection, ∼90% of which were restricted to intermediate endpoints.

Conclusion

In conclusion, there were a number of studies on gastric and liver cancer prevention in developing countries showing promising results after long–term follow–up. Important next steps include pooled meta–analyses as far as possible given the heterogeneity between studies as well as implementation research.

Early and long term anamnestic response to HBV booster dose among fully vaccinated Egyptian children during infancy

OBJECTIVE

To evaluate early and long term anamnestic response to a booster dose of HBV vaccine among non-seroprotected children.

SUBJECTS AND METHOD

A national community based project was carried out on 3600 children aged 9 months to 16 years, fully vaccinated during infancy. They were recruited from 6 governorates representing Egypt. It revealed that 1535 children (42.8%) had non sero-protective anti-HBs (<10 IU/L) and were HBsAg or anti-HBc negative. A challenging dose of 10 μg of mono-valent Euvax HBV vaccine was given to 1121/1535 children. Quantitative assessment of anti-HBs was performed to detect early (2-4 weeks) and long term (one year) anamnestic responses.

RESULTS

Early anamnestic response developed among 967/1070 children (90.3%).Children having detectable anti-HBs (1-9 IU/L) significantly developed early anamnestic response (90%) compared to 85% with undetectable anti-HBs (<1 IU/L), P < 0.001. Multiple logistic analysis revealed that undetectable anti-HBs, living in rural residence and children aged 15-16 years were the most significant predicting risk factors for the absence of early anamnestic response (<10 IU/L), with AOR 2.7, 2.7 & 4.7 respectively. After one year, long term anamnestic response was absent among 15% of children who previously showed early response. Poor early anamnestic response and undetectable pre-booster anti-HBs were the significant predicting risk factors for absent long term anamnestic response, with AOR 18.7 & 2.7 respectively.

CONCLUSION

Immunological memory for HBV vaccine outlasts the presence of anti- HBs and HBV vaccination program provides effective long term protection even in children showing waning or undetectable concentrations of anti-HBs. This signifies no need for a booster dose especially to healthy children.

The effects of booster vaccination of hepatitis B vaccine on children 5-15 years after primary immunization: A 5-year follow-up study

The aim of this study was to evaluate changes in hepatitis B surface antibody titers (anti-HBs) after booster vaccinations in children aged 5-15 y and to provide suitable immunization strategies. A total of 2208 children were initially enrolled in screening, and 559 children were finally included. The participants were divided into 2 groups according to their pre-booster anti-HBs levels: Group I, <10 mIU/ml and Group II, ≥10 mIU/ml. Group I was administered 3 doses of booster hepatitis B vaccine (0-1-6 months, 10 μg), and Group II was administered 1 dose of booster hepatitis B vaccine (10 μg). The antibody titer changes were examined at 4 time points: 1 month after dose 1 and dose 3, and 1 year and 5 years after dose 3. The protective seroconversion rates at those points were 95.65%, 99.67%, 97.59% and 91.05% (p < 0.001), respectively, in Group I, and 100.00%, 99.87%, 99.66% and 98.21% (χ² = 6.04, p = 0.11), respectively, in Group II. The GMT in subjects aged 5-9 y were higher than that in subjects aged 10-15 y in both Group I and Group II at 1 month after dose 1, but no difference was observed at the other three time points. This study demonstrates that booster vaccination has a good medium-term effect. A booster dose for subjects with protective antibodies is not necessary but effective, and 3 doses of hepatitis B vaccination are recommended for those who have lost immunological memory. Receiving booster immunization at the age of 10-15 years may be more appropriate for individuals living in HBV high epidemic areas.

Establishing contemporary trends in hepatitis B sero-epidemiology in an Indigenous population

BACKGROUND

Indigenous populations globally are disproportionately affected by chronic hepatitis B virus (HBV) infection however contemporary sero-prevalence data are often absent. In the Indigenous population of the Northern Territory (NT) of Australia the unique C4 sub-genotype of HBV universally circulates. There are no studies of the sero-prevalence, nor the impact of the vaccination program (which has a serotype mismatch compared to C4), at a population-wide level.

METHODS

We examined all available HBV serology results obtained from the three main laboratories serving NT residents between 1991 and 2011. Data were linked with a NT government database to determine Indigenous status and the most recent test results for each individual were extracted as a cross-sectional database including 88,112 unique individuals. The primary aim was to obtain a contemporary estimate of HBsAg positivity for the NT by Indigenous status.

RESULTS

Based on all tests from 2007-2011 (35,633 individuals), hepatitis B surface antigen (HBsAg) positivity was 3·40% (95%CI 3·19-3·61), being higher in Indigenous (6·08%[5·65%-6·53%]) than non-Indigenous (1·56%[1·38%-1·76%]) Australians, p<0·0001. Birth cohort analysis showed HBsAg positivity fell over time for Indigenous people, with this decrease commencing prior to universal infant vaccination (which commenced in 1990), with an ongoing but slower rate of decline since 1990, (0·23% decrease per year versus 0·17%).

CONCLUSIONS

HBsAg positivity is high in the NT, particularly in the Indigenous population. HBsAg positivity has fallen over time but a substantial part of this decrease is due to factors other than the universal vaccination program.

Long-term persistence in protection and response to a hepatitis B vaccine booster among adolescents immunized in infancy in the western region of China

OBJECTIVES

To evaluate the persistence of protection from hepatitis B (HB) vaccination among adolescents immunized with a primary series of HB vaccine as infants, and the immune response to booster doses.

METHODS

Healthy adolescents aged 15-17 y vaccinated with HB vaccine only at birth were enrolled. Baseline serum hepatitis B surface antigen (HBsAg), antibody against hepatitis B surface antigen (anti-HBs) and antibody against hepatitis B core antigen (anti-HBc) were detected by Enzyme-Linked Immunosorbent Assay (ELISA) and anti-HBs level was measured using Chemiluminescent Microparticle Immunoassay (CMIA). The rate of HBV infection was calculated. The seroprotection rate of anti-HBs (≥ 10 mIU/ml) and GMC level were used to evaluate the persistence of immunity from HB vaccination. Those with anti-HBs < 10 mIU/ml were immunized with booster doses of HB vaccine and the anamnestic response was assessed.

RESULTS

Of 180 adolescents who received a primary series of HB vaccinations as infants, 3 (1.7%) had HBV infection and 74 (41.1%) had anti-HBs ≥ 10 mIU/ml with a GMC of 145.11 mIU/ml. The remaining 103 (57.2%) with anti-HBs < 10 mIU/ml received a booster dose of 20 μg HB vaccine and achieved the seroprotection rate of 84% (84/100) and a GMC of 875.19 mIU/ml at one month post-booster. An additional dose of 60 μg HB vaccine was administered to the 16 adolescents with anti-HBs < 10 mIU/ml after the first booster. All of them obtained anti-HBs seroprotection with a GMC of 271.02 mIU/ml at 1.5 months after an additional dose.

CONCLUSIONS

Vaccine-induced immunity persisted for up to 15-17 y in 89.3% (158/177) of participants after a primary HB vaccination in infancy. Administering a booster dose of 20μg HB vaccine elicited an anamnestic immune responses in the majority of individuals with baseline anti-HBs <10 mIU/ml.

Potential role of killer immunoglobulin receptor genes among individuals vaccinated against hepatitis B virus in Lebanon

AIM

To explore the role of killer immunoglobulin receptor (KIR) genes in responsiveness or non-responsiveness to vaccination against hepatitis B virus.

METHODS

We recruited 101 voluntary participants between March 2010 and December 2011. Sera samples from vaccinated and non-vaccinated participants were tested for the presence of anti-HBs antibodies as a measure of protection against hepatitis B, hepatitis B surface antigen and hepatitis B core antibody as indicators of infection by enzyme-linked immunosorbent assay. KIR gene frequencies were determined by polymerase chain reaction.

RESULTS

Sera samples from 99 participants were tested for the levels of anti-HBs as an indicator of protection (≥ 10 mIU/mL) following vaccination as defined by the World Health Organization international reference standard. Among the vaccinated participants, 47% (35/74) had anti-HBs titers above 100 mIU/mL, 22% (16/74) had anti-HBs ranging between 10-100 mIU/mL, and 20% (15/74) had values of less than 10 mIU/mL. We report the lack of significant association between the number of vaccine dosages and the titer of antibodies among our vaccinated participants. The inhibitory KIR2DL1, KIR2DL4, KIR3DL1, KIR3DL2, and KIR3DL were detected in more than 95%, whereas KIR2DL2, KIR2DL3, KIR2DL5 (KR2DL5A and KIR2DL5B) were expressed in 56%, 84% and 42% (25% and 29%) of participants, respectively. The observed frequency of the activating KIR genes ranged between 35% and 55% except for KIR2DS4, detected in 95% of the study participants (40.6% 2DS4*001/002; 82.2% 2DS4*003/007). KIR2DP1 pseudogene was detected in 99% of our participants, whereas KIR3DP*001/02/04 and KIR3DP1*003 had frequencies of 17% and 100%, respectively. No association between the frequency of KIR genes and anti-HBs antibodies was detected. When we compared the frequency of KIR genes between vaccinated individuals with protective antibodies titers and those who lost their protective antibody levels, we did not detect a significant difference. KIR2DL5B was significantly different among different groups of vaccinated participants (group I > 100 mIU/mL, group II 10-100 mIU/mL, group III < 10 mIU/mL and group IV with undetectable levels of protective antibodies).

CONCLUSION

To our knowledge, this is the first study screening for the possible role of KIR genes among individuals vaccinated against hepatitis B virus (HBV). Our results can be used to design larger studies to better understand the role of KIR genes in protection against or susceptibility to HBV post vaccination.

Low prevalence of hepatitis B vaccine escape mutants among individuals born after the initiation of a nationwide vaccination program in Iran

A nationwide hepatitis B virus (HBV) vaccination program for neonates was launched in Iran in 1993. Despite the success of this program, concern about its long-term success still remains, because breakthrough infections due to emergence of surface mutants have been reported in immunized children. We aimed to evaluate the seroprevalence of HBV and vaccine escape mutants among individuals born after the initiation of the nationwide vaccination program in Iran. This study included 1115 participants younger than 23 years old, with 223 in each age cohort. The presence of HBsAg, anti-HBs and anti-HBc was evaluated using an ELISA kit. HBV-DNA levels were measured in anti-HBc and/or HBsAg-positive subjects. PCR products were sequenced and mutations were identified. The overall HBsAg prevalence was 0.27 %. Anti-HBs and anti-HBc positive rates were 48 % and 0.18 %, respectively. Two individuals were positive for anti-HBc, one of whom was also positive for HBsAg, and the other was positive for anti-HBc only. HBV DNA was detected in three out of four anti-HBc-and /or HBsAg-positive subjects. An I195M mutation within the S gene was detected in two of the three HBV-DNA-positive cases. A very low prevalence of HBsAg and isolated anti-HBc were found in this study. The I195M mutation found in the surface gene could have been induced by immune pressure. Although the number of ''vaccine escape'' mutants found in this cohort was low, ongoing surveillance of breakthrough infections and escape mutants is still needed.

Response to anti-HBV vaccine and 10-year follow-up of antibody levels in healthcare workers

BACKGROUND

Despite improvements in public health and antiviral treatments, vaccination is still the most effective means of prevention of hepatitis B virus (HBV) infection. However, little is known about the duration of protection given by the anti-HBV vaccine. Healthcare workers represent a category at risk not only of contracting infection but also of being a source of contagion to patients.

OBJECTIVES

To assess individual responses to the anti-HBV vaccine and duration of protection 10 years after its administration in a cohort of healthcare workers employed by the University Hospital 'G. Martino' in Messina, Italy.

METHODS

One hundred and seventy medical staff who had been vaccinated following an incident carrying risk of HBV infection were included in this study. The group was followed over a 10-year period, and HBV antibody levels were assessed using an automated microparticle enzyme immunoassay.

RESULTS

Protective antibody levels (≥10 mIU/ml) were found in 65% of subjects who had completed the full vaccine schedule (three doses) and in 35% of subjects who had only received one or two doses of anti-HBV vaccine. Moreover, 10 years after vaccination, HBV antibody levels were inversely related to age at vaccination (P < 0.001). No differences were found between males and females.

CONCLUSIONS

This study, in line with the literature, shows the importance of completing the full vaccine schedule (three doses). Moreover, in order to have an effective and durable antibody response and avoid the risk of contracting HBV after an injury at work, it is important to recommend anti-HBV vaccination at a young age, ideally during childhood in accordance with the national vaccination policy.

Booster dose vaccination for preventing hepatitis B

BACKGROUND

Antibodies against hepatitis B surface antigen (HBsAg) wane over time following hepatitis B immunisation; hence, it is unclear whether people vaccinated in three-dose or four-dose schedules of the hepatitis B vaccine are still immune when the hepatitis B surface antibody (anti-HBs) level in their body is undetectable, or lower than the level usually considered protective. This question may potentially be answered indirectly by measuring the anamnestic immune response to a booster dose of vaccine. The term 'booster' (or revaccination) refers to an additional dose of hepatitis B vaccine (HBV) given some time post-primary vaccination to induce immune memory and improve protection against hepatitis B virus (HBV) infection.

OBJECTIVES

To assess the benefits and harms of booster dose hepatitis B vaccination, more than five years after the primary vaccination, for preventing HBV infection in healthy individuals previously vaccinated with the hepatitis B vaccine, and with hepatitis B surface antibody (anti-HBs) levels below 10 mIU/mL.

SEARCH METHODS

We searched the Cochrane Hepato-Biliary Group Controlled Trials Register, the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, EMBASE, Science Citation Index Expanded, conference databases, and reference lists of articles to January 2016. We also contacted authors of articles. In addition, we searched ClinicalTrials.gov and the World Health Organization (WHO) International Clinical Trials Registry Platform for ongoing trials (May 2016).

SELECTION CRITERIA

Randomised clinical trials addressing anamnestic immune response to a booster dose of hepatitis B vaccine, more than five years after the primary vaccination, in apparently healthy participants, vaccinated in a three-dose or four-dose schedule of the hepatitis B vaccine during the primary vaccination, without receiving an additional dose or immunoglobulin.

DATA COLLECTION AND ANALYSIS

Both review authors decided if the identified studies met the inclusion criteria or not. Primary outcomes included the proportion of participants with anamnestic immune response in non-protected participants and signs of HBV infection. Secondary outcomes were the proportion of participants that developed local and systemic adverse events following a booster dose injection. We planned to report the weighted proportion with 95% confidence intervals (CIs).

MAIN RESULTS

There were no eligible randomised clinical trials fulfilling the inclusion criteria of this review.

AUTHORS' CONCLUSIONS

We were unable to include any randomised clinical trials on the topic; only randomised clinical trials will be able to provide an answer as to whether a booster dose vaccination is able to protect against hepatitis B infection.

Acute Hepatitis B After the Implementation of Universal Vaccination in Italy: Results From 22 Years of Surveillance (1993-2014)

BACKGROUND

Hepatitis B vaccination has proven to be very safe and highly effective. This study assessed the proportion of successfully vaccinated individuals among cases with acute hepatitis B, the proportion of preventable cases if individuals were vaccinated as recommended, and the reasons for failures.

METHODS

We analyzed data reported to the Italian Surveillance System for Acute Viral Hepatitis from 1993 to 2014.

RESULTS

A total of 362 of 11 311 (3.2%) cases with acute hepatitis B were vaccinated. Of the 277 cases for whom immunization data were available, 50 (18%) received a complete vaccination course according to the correct schedule and before exposure to hepatitis B virus. Molecular characterization of 17 of these cases showed that 6 were infected with S-gene mutants. Among the 10 949 unvaccinated cases, 213 (1.9%) escaped mandatory vaccination and 2821 (25.8%) were not vaccinated despite being at increased risk of infection. Among the latter, the most common risk factors were cohabitation with hepatitis B surface antigen (HBsAg) carriers, intravenous drug use, and homosexual/bisexual practices. Thirty-seven percent of the unvaccinated households with HBsAg carriers were aware of their risk. Lack of trust in the vaccination, negative attitude, and inaccurate beliefs followed by lack of or poor communication and low perceived severity of the disease were the most frequent reasons for vaccine hesitancy.

CONCLUSIONS

Development of acute disease in successfully vaccinated individuals is a rare event. Further efforts are needed to enhance the vaccine coverage rate in individuals at increased risk of infection.

Immune response to second vaccination series of hepatitis B virus among booster dose non-responders

OBJECTIVE

To evaluate the response to second vaccination series among post-booster sero-negative children who had previously received compulsory HBV vaccination.

SUBJECTS AND METHODS

After given a booster dose to 1070 children, 103 of them failed to generate anamnestic response (anti-HBs <10 IU/L). Only 91/103 children received additional two doses of recombinant HBV vaccine (i.e. 2(nd) vaccination series) after 1 and 6 months post-booster. Blood sample was withdrawn aseptically one month later for quantitative assessment of anti-HBs to detect development of protective immune response (≥10 IU/L). Immunological vaccination failure was assigned to children who did not develop protective immune response after 2(nd) vaccination series.

RESULTS

Protective immune response was detected among 84/91 children (92.3%). While 7/91 (7.7%) whose age were ≥10 years did not respond and had post-booster undetectable anti-HBs. About 80% of children with post-booster detectable anti-HBs showed significant protective immune response (anti-HBs ≥100 IU/L) and higher GMT (299.1 ± 3.6 IU/L) compared to those with undetectable 60% and 106.2 ± 12.9 IU/L respectively (P<0.05). No significant difference was detected as regards gender or residence, P>0.05. All children with history of rheumatic fever (7 children) or diabetes mellitus (1 child) developed immune response after 2(nd) vaccination series.

CONCLUSION

A booster dose of HB vaccine may be unable to induce sufficient immunological response in children who had undetectable anti-HBs titers. Revaccination for non-responders is an important procedure to increase HBV protection rate.

The one year effects of three doses of hepatitis B vaccine as a booster in anti-HBs-negative children 11-15 years after primary immunization; China, 2009-2011

The aim of this study was to evaluate hepatitis B surface antibody (anti-HBs) levels one year after hepatitis B booster vaccination in anti-HBs-negative (<10 mIU/mL) children 11-15 y after primary vaccination. Anti-HBs titers were examined in 235 children who were negative for hepatitis B surface antigen (HBsAg), anti-HBs, and hepatitis B core antibody (anti-HBc). The children were then divided into 3 groups based on their anti-HBs levels pre-booster: Group I, <0 .1 mIU/mL; Group II, 0.1 to <1 .0 mIU/mL; and Group III, 1.0 to <10 .0 mIU/mL. They were vaccinated with 3 doses of hepatitis B vaccine (0-1-6 month, 20 ug), and anti-HBs levels were measured. One month after the first dose, the anti-HBs positive rates (≥ 10 mIU/mL) in Groups I-III were 56.14%, 83.61% and 100%. One month after the third dose, the anti-HBs-positive rates in Groups I-III were 96.49%, 98.36% and 100%. One year after the third dose, the anti-HBs-positive rates in Groups I-III were 73.68%, 75.41% and 98.29%, respectively. Protective levels declined more rapidly for those with lower titers. Children with pre-booster anti-HBs titers of 1-9.9 mIU/mL might not need any booster dose, and the children with pre-booster titers of 0.1-0.9 and <0 .1 mIU/mL might need more than one dose booster vaccination.

Pathology and oncology in Africa: education and training for the future in cancer research– East African Regional Meeting

According to the World Health Organisation (WHO), deaths from non-communicable diseases (NCDs) will increase globally, with the largest increase being on the African continent. On our continent, projections have indicated that deaths from NCDs will exceed all combined communicable, maternal, perinatal and nutritional diseases as the most common causes of death by 2030. Hence, the importance of a functional and improved pathology system in the diagnosis of cancer cannot be debated.

Recently, the African Organization for Research and Training in Cancer (AORTIC) organised its East African regional meeting in Mwanza, Tanzania on 25–26 June 2015, with the focus being ‘Pathology and oncology: Education and training for the future in cancer research’. The main themes of the workshop were around improving cancer care and the role of twinning in Eastern Africa, in particular the Mwanza cancer project, telepathology, e-health and biobanking. The outcomes of a 2 day strategic meeting were developing an efficient and effective plan to guide the improvement in pathology training and cancer research in Africa.

Lessons learnt over two decades of vaccination against hepatitis B in Italy

This article reviews topics covered and discussed at the Meeting: "Vaccini e vaccinazioni. Migliorare l'oggi e preparare il domani", held in Genoa, Italy, on 12 September 2014. Data presented at the meeting, clearly showed that: 1) hepatitis B vaccination can confer long-term protection and there is no need for booster in immunocompetent vaccinees; 2) vaccination is highly effective in protecting population from clinical acute or chronic HBV infections, including hepatocellular carcinoma; 3) children vaccinated as infants with hexavalent vaccines maintain immunological memory 5 years after priming, but further studies are needed to assess whether immunity persists during the adolescence and adulthood when risk of exposure to HBV becomes higher; 4) the emergence of vaccine-escape mutants and Pol-gene mutants during antiviral therapy - which can result in changes in the S-gene - is of some concern, but at present there is no evidence that such mutants may pose a threat to the established programs of vaccination.

Hepatitis B virus antibody levels 7 to 9 years after booster vaccination in Alaska native persons

Hepatitis B antibody persistence was assessed in individuals who had previously received a vaccine booster. We measured hepatitis B surface antigen antibody (anti-HBs) levels 7 to 9 years post-hepatitis B booster in individuals with primary vaccination at birth. While 95 (91.3%) of 104 participants had detectable anti-HBs (minimum, 0.1 mIU/ml; maximum, 1,029 mIU/ml), only 43 (41%) had protective levels of ≥10 mIU/ml. Pre- and week 4 postbooster anti-HBs levels were significant predictors of hepatitis B immunity at follow-up (P < 0.001). Almost all participants had detectable anti-HBs 7 to 9 years after the hepatitis B vaccine booster, but less than half had levels ≥10 mIU/ml.

Prevention of materno-foetal transmission of hepatitis B in sub-Saharan Africa: the evidence, current practice and future challenges

Hepatitis B (HBV) infection is highly endemic in sub-Saharan Africa (SSA), where more than 8% of the population remain chronic HBV carriers. SSA has one of the highest HBV-related liver cancer rates in the world (CA Cancer J Clin, 55, 2005, 74) and HBV-related liver cancer is the most common cause of premature death in West Africa (Lancet Oncol, 9, 2008, 683; Hepatology, 39, 2004, 211). As such, HBV represents a significant global threat to health in the African continent. Most SSA countries have elected to vaccinate all children against HBV through the WHO-sponsored Expanded Program of Immunization and the current recommendation from WHO-AFRO is for birth-dose HBV vaccination to prevent maternal/child transmission (MFT) and early horizontal transmission of HBV. However, in Africa, HBV vaccine coverage remains low and HBV birth-dose vaccination has not been implemented. HBV transmission from mother to child in the early perinatal period therefore remains a significant contributor to the burden of HBV-related disease in SSA. This review explores the evidence for materno-foetal transmission of HBV in SSA, outlining current practice for HBV MFT prevention and identifying the significant challenges to implementation of HBV prevention in SSA.

Efficacy and effectiveness of infant vaccination against chronic hepatitis B in the Gambia Hepatitis Intervention Study (1986-90) and in the nationwide immunisation program

BACKGROUND

Gambian infants were not routinely vaccinated against hepatitis B virus (HBV) before 1986. During 1986-90 the Gambia Hepatitis Intervention Study (GHIS) allocated 125,000 infants, by area, to vaccination or not and thereafter all infants were offered the vaccine through the nationwide immunisation programme. We report HBV serology from samples of GHIS vaccinees and unvaccinated controls, and from children born later.

METHODS

During 2007-08, 2670 young adults born during the GHIS (1986-90) were recruited from 80 randomly selected villages and four townships. Only 28% (753/2670) could be definitively linked to their infant HBV vaccination records (255 fully vaccinated, 23 partially vaccinated [1-2 doses], 475 not vaccinated). All were tested for current HBV infection (HBV surface antigen [HBsAg]) and, if HBsAg-negative, evidence of past infection (HBV core-protein antibody [anti-HBc]). HBsAg-positive samples (each with two age- and sex-matched HBsAg-negative samples) underwent liver function tests. In addition, 4613 children born since nationwide vaccination (in 1990-2007) were tested for HBsAg. Statistical analyses ignore clustering.

RESULTS

Comparing fully vaccinated vs unvaccinated GHIS participants, current HBV infection was 0.8% (2/255) vs 12.4% (59/475), p < 0.0001, suggesting 94% (95% CI 77-99%) vaccine efficacy. Among unvaccinated individuals, the prevalence was higher in males (p = 0.015) and in rural areas (p = 0.009), but adjustment for this did not affect estimated vaccine efficacy. Comparing fully vaccinated vs unvaccinated participants, anti-HBc was 27.4% (70/255) vs 56.0% (267/475), p < 0.00001. Chronic active hepatitis was not common: the proportion of HBsAg-positive subjects with abnormal liver function tests (ALT > 2 ULN) was 4.1%, compared with 0.2% in those HBsAg-negative. The prevalence of antibodies to hepatitis C virus was low (0.5%, 13/2592). In children born after the end of GHIS, HBsAg prevalence has remained low; 1.4% (15/1103) in those born between 1990-97, and 0.3% (9/35150) in those born between 1998-2007.

CONCLUSIONS

Infant HBV vaccination achieves substantial protection against chronic carriage in early adulthood, even though approximately a quarter of vaccinated young adults have been infected. This protection persists past the potential onset of sexual activity, reinforcing previous GHIS findings of protection during childhood and suggesting no need for a booster dose. Nationwide infant HBV vaccination is controlling chronic infection remarkably effectively.

Hepatitis B and C infection: is it a problem in Polish healthcare workers?

OBJECTIVES

Hepatitis B (HBV) and C viruses (HCV) are among the most frequent blood borne pathogens. According to WHO, 5% of healthcare workers (in central Europe), are exposed to at least one sharps injury contaminated with HBV per year, 1,7% - contaminated with HCV.

AIMS

The aims of the study were to determine prevalence of HCV and HBV infections, vaccination efficacy against hepatitis B and usefulness of alanine aminotransferase (ALT) testing in prophylactic examinations in healthcare workers (HCWs).

MATERIAL AND METHODS

In a group of 520 healthcare workers, a survey, laboratory and serologic tests such as ALT, HBsAg, anti-HBs, anti-HBcT and anti-HCV were carried out.

RESULTS

The study revealed a low rate of workers with presence of HBsAg and anti-HCV (1,2% and 0,8% respectively). Anti-HBcT was found in 99 subjects (19%) without a significant association with experiencing an occupational percutaneous injury. Being vaccinated against HBV was declared by 90% of the subjects. There was no relationship between ALT level rise and positive HBsAg, anti-HCV and anti-HBcT tests.

CONCLUSION

A seroprevalence of HBV and HCV markers in HCWs found in the study is low and similar to the one found in general population. Current or past hepatitis B infections were independent of needle stick injuries. Vaccination against HBV coverage, although found to be high, should improve to 100%. Occupational prophylactic medical examinations found performing ALT test (obligatory in Poland for HCWs) not helpful. It seems that determination of anti-HBcT and anti-HCV status would be essential in pre-employment medical examinations.

Molecular epidemiology of hepatitis B in the Indigenous people of northern Australia

BACKGROUND AND AIM

The hepatitis B surface antigen was first described in the blood of an Indigenous Australian man, yet little is known about its molecular epidemiology in this population, in which it is endemic. The study aimed to determine the clinical and molecular epidemiology of hepatitis B virus (HBV) in Indigenous people from northern Australia.

METHODS

Following ethics approval and informed consent, blood specimens and clinical details from Indigenous adults known to be infected with HBV and who were born and raised in Indigenous communities in northern Australia were obtained. HBV genotypes were determined in isolates with sufficient HBV DNA by polymerase chain reaction by sequencing of the polymerase/surface gene.

RESULTS

Between June 2010 and June 2012, 65 patients were recruited from six different regions of northern Australia. Thirty-two patients (49%) were hepatitis B e-antigen-positive, and 48% were hepatitis B e-antibody-positive. No patients were found to be coinfected with hepatitis C virus or human immunodeficiency virus. Of the 49 samples with sufficient viral load for genotyping, 100% were infected with genotype C4, previously only reported from two Indigenous Australians. All isolates had wild-type polymerase gene sequences despite 14 currently or previously receiving antiviral treatment. The canonical sG145R vaccine-escape variant was detected in the surface antigen of virus from two patients.

CONCLUSIONS

The exclusive HBV genotype in this ancient population is genotype C4. Whole genome sequencing and clinical follow-up of this cohort are in progress, with the aim of exploring the clinical significance of these findings.

Long-term persistence of immunity after vaccination of pre-adolescents with low doses of a recombinant hepatitis B vaccine

BACKGROUND AND AIMS

Recent studies have shown no detectable antibodies and no response to a challenge dose of vaccine 10-20 y after receiving low doses (2.5-5 µg) of recombinant hepatitis B vaccine during first months of life. Little information is available on long-term persistence of immunity after vaccinating pre-adolescents with low doses of hepatitis B vaccine.

RESULTS

The results of 560 subjects were included in this analysis. All subjects had a seroprotective antibody titer (≥10 IU/L) one month post-primary vaccination; 5, 10 and 15 y post-vaccination 95%, 95% and 87% had detectable antibodies, and 82%, 86%, and 68% had a seroprotective antibody titer; GMTs were 73 IU/L, 89 IU/L, and 28 IU/L, respectively. More than 99.4% of subjects had an anamnestic response to a challenge dose of vaccine given 5, 10, or 15 y post-vaccination. Five and ten years post-booster dose 97% and 95% of subjects still have a seroprotective anti-HBs titer with GMTs 16-18-fold higher when compared with those observed 5-10 y post-primary vaccination.

MATERIALS AND METHODS

This randomized trial was initiated in 1996 with the main objective to assess the persistence of antibodies and immune memory 5, 10 and 15 y after vaccinating 8-10 y-old children with three doses of Recombivax 2.5 µg, as well as the short and long-term effect of a booster dose given at different intervals.

CONCLUSIONS

Virtually all children vaccinated at the age of 8-10 y with low doses of hepatitis B vaccine still have an excellent immune memory up to age of 25 y. The results of this study do not support the use of booster doses.

Observational study of vaccine efficacy 24 years after the start of hepatitis B vaccination in two Gambian villages: no need for a booster dose

Objectives

To determine the duration of protection from hepatitis B vaccine given in infancy and early childhood and asses risk factors for HBV infection and chronic infection.

Methods

In 1984 infant HBV vaccination was started in two Gambian villages. Cross sectional serological surveys have been undertaken every 4 years to determine vaccine efficacy. In the current survey 84.6% of 1508 eligible participants aged 1–28 years were tested. A spouse study was conducted in females (aged 14 years and above) and their male partners.

Results

Vaccine efficacy against chronic infection with hepatitis B virus was 95.1% (95% confidence interval 91.5% to 97.1%), which did not vary significantly between age groups or village. Efficacy against infection was 85.4% (82.7% to 87.7%), falling significantly with age. Concentrations of hepatitis B antibody fell exponentially with age varying according to peak response: 20 years after vaccination only 17.8% (95% CI 10.1–25.6) of persons with a low peak response (10–99 mIU/ml) had detectable HBs antibody compared to 27% (21.9% to 32.2%) of those with a high peak response (>999 mIU/ml). Time since vaccination and a low peak response were the strongest risk factors for HBV infections; males were more susceptible, marriage was not a significant risk for females. Hepatitis B DNA was not detected after infection, which tested soley core antibody positive. An undetectable peak antibody response of <10 mIU/ml and a mother who was hepatitis B e antigen positive were powerful risk factors for chronic infection.

Conclusions

Adolescents and young adults vaccinated in infancy are at increased risk of hepatitis B infection, but not chronic infection. Married women were not at increased risk. There is no compelling evidence for the use of a booster dose of HBV vaccine in The Gambia.

Hepatitis B vaccination: a completed schedule enough to control HBV lifelong? Milan, Italy, 17-18 November 2011

The Viral Hepatitis Prevention Board (VHPB) organized an international meeting in Milan in November 2011 on the question of whether completing a course of hepatitis B vaccination confers lifelong protection against hepatitis B virus infection and its complications. Presentations covered vaccine efficacy including factors influencing long-term protection; breakthrough infections; the immunological effect of natural boosting; the effectiveness of universal hepatitis B vaccination in different countries, and issues relating to national, regional and global policies on booster vaccination. Findings from four continents were presented at the meeting, with data now extending to follow-up for nearly 30 years after full primary vaccination. The results reported add to the extensive and growing body of knowledge, demonstrating that in spite of subsequent decline and ultimate loss of detectable serum anti-HBs, a full primary course of hepatitis B vaccine confers complete protection against acute clinical disease and chronic hepatitis B infection for long periods of time. Our understanding of the role and functions of T and B cells in protective immunity deepens, although the picture is still complex. A framework for future work in several areas emerged from the meeting, including monitoring and surveillance of vaccination programmes, breakthrough infections, hepatitis B in immigrant populations, and vaccine-escape viral mutants. One further concrete recommendation is the setting up of a working group to standardize definitions on terms such as "immunity", "protection", "immune memory", "non-responders", "long-term", "anamnestic response", "breakthrough" and "vaccine failure".

Twenty years of universal vaccination against hepatitis B in Italy: achievements and challenges

Viral hepatitis B is a vaccine-preventable disease. Vaccination has proved to be safe and highly effective in reducing the incidence, the carrier rate and HBV-related mortality on a global scale. In Italy, universal vaccination against hepatitis B started in 1991 in infants as well as in adolescents, providing an outstanding record of safety and effectiveness. Within a few years, over 95% coverage was consistently reported. Today, some 17 million people are immune against hepatitis B and their immunity has been shown to be long-lasting. At present, no booster is required in healthy vaccinated people to sustain protection. Surveillance data from Italy have shown a clear overall decline in hepatitis B among successfully vaccinated individuals. Furthermore, a generation of children and young people (at present cohorts ranging from 0 to 32 years) is emerging with practically no markers of HBV infection. Italy’s vaccination programme has resulted in substantial progress towards the prevention and control of hepatitis B. The vaccination programme must continue. Maintaining mandatory vaccination of infants and increasing HBV vaccination coverage in high-risk groups, including households of HBsAg carriers as well as immigrants, remain a priority for the future.

Thymic function and T cell parameters in a natural human experimental model of seasonal infectious diseases and nutritional burden

BACKGROUND

The study exploits a natural human experimental model of subsistence farmers experiencing chronic and seasonally modified food shortages and infectious burden. Two seasons existed, one of increased deprivation and infections (Jul-Dec), another of abundance and low infections (Jan-Jun); referred to as the hungry/high infection and harvest/low infection seasons respectively. Prior analysis showed a 10-fold excess in infectious disease associated mortality in young adults born in the hungry/high infection versus harvest/low infection season, and reduced thymic output and T cell counts in infancy. Here we report findings on the role of early life stressors as contributors to the onset of T cell immunological defects in later life.

METHODS

We hypothesised that season of birth effects on thymic function and T cell immunity would be detectable in young adults since Kaplan-Meier survival curves indicated this to be the time of greatest mortality divergence. T cell subset analyses by flow-cytometry, sjTRECs, TCRVβ repertoire and telomere length by PCR, were performed on samples from 60 males (18-23 y) selected to represent births in the hungry/high infection and harvest/low infection

RESULTS

Total lymphocyte counts were normal and did not differ by birth season. CD3+ and CD4+ but not CD8+ counts were lower for those born during the hungry/high infection season. CD8+ telomere length also tended to be shorter. Overall, CD8+ TCRVβ repertoire skewing was observed with 'public' expressions and deletions seen in TCRVβ12/22 and TCRVβ24, respectively but no apparent effect of birth season.

CONCLUSIONS

We conclude that, although thymic function was unchanged, the CD4+ and CD3+ counts, and CD8+ telomere length results suggested that aspects of adult T cell immunity were under the influence of early life stressors. The endemicity of CMV and HBV suggested that chronic infections may modulate immunity through T cell repertoire development. The overall implications being that, this population is at an elevated risk of premature immunosenescence possibly driven by a combination of nutritional and infectious burden.

Evidence of protection against clinical and chronic hepatitis B infection 20 years after infant vaccination in a high endemicity region

Vaccination against hepatitis B virus (HBV) immediately after birth prevents neonatal infection by vertical transmission from HBV carrier mothers. There is an ongoing debate whether infant vaccination is sufficient to protect against infection when exposed to HBV later in life. We studied 222 Thai infants born to HBsAg -/+ and HBeAg -/+ mothers who were vaccinated with recombinant hepatitis B vaccine at 0-1-2-12 months of age. A subset of 100 subjects received a booster dose at age 5 years. Blood samples collected yearly for 20 years were examined for anti-HBs antibodies and serological markers of hepatitis B infection (anti-HBc, HBsAg, and in selected cases HBeAg, anti-HBe, HBV DNA). During the 20-year follow-up, no subject acquired new chronic HBV infection or clinical hepatitis B disease. During the first decade, possible subclinical breakthrough HBV infection (anti-HBc seroconversion) was only observed in subjects born to HBsAg +/HBeAg + mothers (6/49 [12.2%]). During the second decade, breakthrough HBV infections were detected in all groups (18/140 [12.8%]). Increases in anti-HBs concentrations that were unrelated to additional HBV vaccination or infection were detected in approximately 10% of subjects in each decade. Primary infant vaccination with a recombinant hepatitis B vaccine confers long-term protection against clinical disease and new chronic hepatitis B infection despite confirmed hepatitis B exposure.

Percutaneous exposure incidents in nurses: Knowledge, practice and exposure to hepatitis B infection: Percutaneous exposure incidents in nurses

BACKGROUND

Nurses are at risk of percutaneous exposure incidents (PEIs), which may lead to serious or even fatal blood-borne infections.

OBJECTIVES

To determine the prevalence of PEIs in the last year, among nurses and to assess their knowledge about and frequency of safe method of practice in exposure to blood-borne pathogens (especially, to HBV).

MATERIALS AND METHODS

A cross-sectional study in 2008 was conducted on 138 nurses working in general surgery and obstetrics/gynecology services of Qazvin University of Medical Sciences, Qazvin, Central Iran. A questionnaire for assessment of risk factors for contracting HBV infection was completed by nurses.

RESULTS

Overall, the prevalence of needle stick injury (NSI) and direct exposure to body fluids were 52.9% (95% CI: 44.5%-61.3%) and 65.4% (95% CI: 57.4% - 73.8%), respectively. There was no statistically significant difference between the two studied centers in terms of sharp injuries; however, the rate of repeated NSI (number per each year ≥3) and mucocutaneous exposures were significantly higher in the general surgery ward. The overall coverage of vaccination in the two studied centers was 96.3%, but the rate of accurate answers to many questions pertaining to knowledge and practice were less than 50%.

CONCLUSIONS

Nurses are still at significant risk for developing NSI and mucocutaneous exposure. Continuous educational programs (especially by highlighting the seriousness of the problem) are necessary for improving this situation because inadequate education might increase unsafely practice.

Booster dose vaccination for preventing hepatitis B

BACKGROUND

Antibodies against hepatitis B surface antigen (HBs) wane over time after vaccination for hepatitis B (HB); hence, the duration of protection provided by the vaccine is still unknown but may be evaluated indirectly by measuring the anamnestic immune response to booster doses of vaccine.

OBJECTIVES

To assess the benefits and harms of booster dose hepatitis B vaccination for preventing HB infection.

SEARCH STRATEGY

We searched The Cochrane Hepato-biliary Group Controlled Trials Register, the Cochrane Central Register of Controlled Trials (CENTRAL) (Issue 4, 2010) in The Cochrane Library, MEDLINE, EMBASE, Science Citation Index Expanded, conference databases, and reference lists of articles to May 2010. We also contacted authors of articles and manufacturers.

SELECTION CRITERIA

Randomised clinical trials addressing anamnestic immune response to booster of HB vaccine five years or more after primary vaccination in apparently healthy participants, vaccinated in a 3-dose or 4-dose schedules of HB vaccine without receiving additional dose or immunoglobulin.

DATA COLLECTION AND ANALYSIS

Two authors made the decisions if the identified publications on studies met the inclusion criteria or not. Primary outcome measures included the proportion with anamnestic immune response in non-protected participants and signs of hepatitis B virus infection. Secondary outcomes were the proportion with local and systemic adverse event events developed following booster dose injection. Weighted proportion were planned to be reported with 95% confidence intervals.

MAIN RESULTS

There were no eligible randomised clinical trials fulfilling the inclusion criteria of this review.

AUTHORS' CONCLUSIONS

We were unable to identify randomised clinical trials on the topic. We need randomised clinical trials to formulate future booster policies for preventing hepatitis B infection.

Lasting immune memory against hepatitis B in children after primary immunization with 4 doses of DTPa-HBV-IPV/Hib in the first and 2nd year of life

BACKGROUND

Few studies have assessed long term persisting immunity against hepatitis B virus (HBV) in children vaccinated during infancy with combined vaccines containing recombinant HBV surface antigen (HBs). We assessed antibody persistence and immune memory in children 4-5 years of age, previously vaccinated with four doses of combined hexavalent DTPa-HBV-IPV/Hib vaccine (Infanrix hexa).

METHODS

Immune memory was assessed in 301 children through administration of a challenge dose of monovalent HBV vaccine.

RESULTS

At 4-5 years of age, 85.3% of subjects had persisting anti-HBs antibody concentrations >or= 10 mIU/mL, rising to 98.6% after the HBV challenge dose. All but 12 subjects (95.8%) achieved post-challenge anti-HBs concentrations >or= 100 mIU/mL. The post-challenge anti-HBs GMC rose by 100-fold compared to pre-challenge concentrations. An anamnestic response to the HBV vaccine challenge was observed in 96.8% of subjects, including 17/21 (81.0%) of children with initially undetectable antibodies (<3.3 mIU/mL). All but 4 of 42 subjects (90.5%) with anti-HBs antibodies <10 mIU/mL prior to the challenge dose, achieved seroprotective levels afterwards. A 4-fold rise in antibody concentration after the challenge dose was observed in 259/264 (98.1%) of initially seropositive subjects. The magnitude of the post-challenge responses was proportional to pre-challenge anti-HBs levels. No serious adverse events were reported during the study.

CONCLUSION

The combined DTPa-HBV-IPV/Hib vaccine induced lasting immune memory against hepatitis B. Long term protection afforded by DTPa-HBV-IPV/Hib is likely to be similar to that observed following priming with monovalent HBV vaccines.

TRIAL REGISTRATION

http://www.clinicaltrials.gov 106789 NCT00411697.