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Hepatitis B vaccination.

ABSTRACT: Hepatitis B virus is a worldwide leading cause of acute and chronic liver disease including cirrhosis and hepatocellular carcinoma. Effective vaccines have been available since the early '80s and vaccination has proved highly successful in reducing the disease burden, the development of the carrier state and the HB-related morbidity and mortality in the countries where vaccination has been implemented. Neutralizing (protective) antibodies (anti-HBs) induced by vaccination are targeted largely towards the amino acid hydrophilic region, referred to as the common a determinant which is present on the outer protein coat or surface antigen (HBsAg), spanning amino acids 124-149. This provides protection against all HBV genotypes (from A to H) and is responsible for the broad immunity afforded by hepatitis B vaccination. Thus, alterations of residues within this region of the surface antigen may determine conformational changes that can allow replication of the mutated HBV in vaccinated people. An important mutation in the surface antigen region was identified in Italy some 25 years ago in infants born to HBsAg carrier mothers who developed breakthrough infections despite having received HBIG and vaccine at birth. This virus had a point mutation from guanosine to adenosine at nucleotide position 587, resulting in aa substitution from glycine (G) to arginine (R) at position 145 in the a determinant. Since the G145R substitution alters the projecting loop (aa 139-147) of the a determinant, the neutralizing antibodies induced by vaccination are no longer able to recognize the mutated epitope. Beside G145R, other S-gene mutations potentially able to evade neutralizing anti-HBs and infect vaccinated people have been described worldwide. In addition, the emergence of Pol mutants associated with resistance to treatment with nucleos(t)ide analogues can select viruses with crucial changes in the overlapping S-gene, potentially able to alter the S protein immunoreactivity. Thus such mutants have the potential to infect both naïve and immunized people, negatively affecting the efficacy of both the antiviral treatment and the vaccination programs. Despite concern, at present the overall impact of vaccine escapes mutants seems to be low and they do not pose a public health threat or a need to modify the established hepatitis B vaccination programs. The development of novel NAs with a high barrier to resistance is warranted.

SUBMITTER: Romano L

PROVIDER: S-EPMC4514213 | biostudies-other | 2015

REPOSITORIES: biostudies-other

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Project description:BackgroundDespite being considered as a low prevalence country for hepatitis B (HBV), some populations in Germany are at higher risk of infection. In the context of the World Health Organization's (WHO) viral hepatitis elimination goals, a valid epidemiological data base is needed to plan and monitor the national response. Prevention strategies include general and targeted HBV vaccination programmes.ObjectiveThe aim of this work was to estimate the HBV vaccination coverage (VC) in the general population (GP) and different population groups in Germany from available evidence and to identify current evidence gaps for future research.MethodsWe conducted a systematic review on HBV VC in the general population and populations at high risk of HBV exposure or severe infection in Germany. We included eligible publications (01/01/2017 to 06/06/2020) from databases Embase, Pubmed and Livivo, from a previous scoping review (including data published 01/01/2005-17/03/2017), from the national surveillance system and screened the reference lists of all publications at full text level. Risk of bias was assessed using the Hoy et al. tool.ResultsWe included 68 publications of 67 studies and assigned them to one or more suitable population groups. Twenty-one studies contained data among children/adolescents and three among adults from the GP (VC 65.8-90.5% and 22.9-52.1%, respectively), one among travelers (VC 89.0%), 13 among immunocompromised populations (VC 7.8-89.0%), 16 among populations with occupational risk and 16 with non-occupational risk of HBV exposure (VC 63.6-96.5% and 4.4-84.5%, respectively).ConclusionComprehensive evidence at low risk of bias was identified for children/adolescents. However, 25 years after including HBV in the national immunisation schedule, VC in Germany is still below the 95%-goal defined by WHO. For people at occupational risk of HBV exposure, VC was mostly reported to be over the WHO goal of 80%, but quality of evidence was heterogenous and should be improved. For people at non-occupational risk of HBV exposure, evidence was sparse and of low quality. The low VC highlights the need for future research to plan vaccination programmes targeting these populations.

Project description:ObjectivesNation-wide hepatitis B vaccination coverage among healthcare workers (HCWs) is not well researched in China. This study aims to investigate the self-reported hepatitis B vaccination status among HCWs in China.MethodsWe conducted a cross-sectional survey of health_care workers' vaccination statuses in 120 hospitals in China by collecting demographic and vaccination data. Univariate and multivariate logistic regression analysis were used to assess factors associated with hepatitis B vaccination coverage.ResultsEighty-six percent (2,666/3,104) of respondents reported having received at least one dose of the hepatitis B vaccination and 60% (1,853/3,104) reported having completed ≥3 doses of the hepatitis B vaccination. Factors associated with completing ≥3 doses of the hepatitis B vaccination included workplaces offering free hepatitis B vaccination with vaccination management, age, medical occupation, hospital level, acceptable hepatitis B knowledge and having received training on hepatitis B. HCWs in workplaces offering a free hepatitis B vaccine with vaccination management were 1.4 times more likely (OR = 1.4, 95% CI: 1.1-1.8) to complete their hepatitis B vaccination compared to HCWs in workplaces that did not offer a free hepatitis B vaccine. Either the possession of acceptable hepatitis B knowledge or an age of 30-39 years increased the odds of complete hepatitis B vaccination by 1.3-fold (95% CIs: 1.1-1.5 and 1.1-1.7, respectively) over their referent category. The receipt of training on hepatitis B was also associated with a higher percentage of completing the hepatitis B vaccination (OR = 1.5, 95% CI: 1.2-1.8). The main self-reported reason for incomplete hepatitis B vaccination was "forgot to complete follow-up doses" among 43% (234/547) of respondents. Among those who never received any hepatitis B vaccination, only 30% (131/438) intended to be vaccinated. Obtaining immunity from work (40%) and hospitals that did not provide hepatitis B vaccination activities (40%) were the top reasons mentioned for refusing hepatitis B vaccination.ConclusionsThe complete hepatitis B vaccination rate among HCWs in China is low, and the desire of HCWs for vaccination is indifferent; therefore, education campaigns are needed. In addition, a free national hepatitis B vaccination policy for HCWs that includes vaccination management should be prioritized to improve hepatitis B coverage among HCWs who are at-risk for HBV infection.

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Hepatitis B vaccination.

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