The investigation of a 'cluster' of hepatitis B in teenagers from an indigenous community in North Queensland

Chronic hepatitis B in remote, tropical Australia; successes and challenges

Introduction

Aboriginal and Torres Strait Islander Australians living in remote locations suffer disproportionately from chronic hepatitis B (CHB). Defining the temporospatial epidemiology of the disease—and assessing the ability of local clinicians to deliver optimal care—is crucial to improving patient outcomes in these settings.

Methods

The demographic, laboratory and radiology findings in all patients diagnosed with CHB after 1990, and presently residing in remote Far North Queensland (FNQ), tropical Australia, were correlated with their management and clinical course.

Results

Of the 602 patients, 514 (85%) identified as Aboriginal and Torres Strait Islander Australians, 417 (69%) of whom had Torres Strait Islander heritage. Among the 514 Aboriginal and Torres Strait Islander Australians, there were only 61 (12%) born after universal postnatal vaccination was introduced in 1985. Community CHB prevalence varied significantly across the region from 7/1707 (0.4%) in western Cape York to 55/806 (6.8%) in the Eastern Torres Strait Islands. Although 240/602 (40%) are engaged in care, with 65 (27%) meeting criteria for antiviral therapy, only 43 (66%) were receiving this treatment. Among 537 with complete data, 32 (6%) were cirrhotic, of whom 15 (47%) were engaged in care and 10 (33%) were receiving antiviral therapy. Only 64/251 (26%) in whom national guidelines would recommend hepatocellular carcinoma (HCC) surveillance are receiving screening, however, only 20 patients have been diagnosed with HCC since 1999.

Conclusion

Vaccination has had a dramatic effect on CHB prevalence in FNQ in only a generation. However, although engagement in care is the highest in Australia, this is not translating into initiation of antiviral therapy in all those that should be receiving it, increasing their risk of developing cirrhosis and HCC. New strategies are necessary to improve the care of Indigenous Australians living with CHB to reduce the morbidity and mortality of this preventable disease.

Immunization information systems to increase vaccination rates: a community guide systematic review

CONTEXT

Immunizations are the most effective way to reduce incidence of vaccine-preventable diseases. Immunization information systems (IISs) are confidential, population-based, computerized databases that record all vaccination doses administered by participating providers to people residing within a given geopolitical area. They facilitate consolidation of vaccination histories for use by health care providers in determining appropriate client vaccinations. Immunization information systems also provide aggregate data on immunizations for use in monitoring coverage and program operations and to guide public health action.

EVIDENCE ACQUISITION

Methods for conducting systematic reviews for the Guide to Community Preventive Services were used to assess the effectiveness of IISs. Reviewed evidence examined changes in vaccination rates in client populations or described expanded IIS capabilities related to improving vaccinations. The literature search identified 108 published articles and 132 conference abstracts describing or evaluating the use of IISs in different assessment categories.

EVIDENCE SYNTHESIS

Studies described or evaluated IIS capabilities to (1) create or support effective interventions to increase vaccination rates, such as client reminder and recall, provider assessment and feedback, and provider reminders; (2) determine client vaccination status to inform decisions by clinicians, health care systems, and schools; (3) guide public health responses to outbreaks of vaccine-preventable disease; (4) inform assessments of vaccination coverage, missed vaccination opportunities, invalid dose administration, and disparities; and (5) facilitate vaccine management and accountability.

CONCLUSIONS

Findings from 240 articles and abstracts demonstrate IIS capabilities and actions in increasing vaccination rates with the goal of reducing vaccine-preventable disease.

Chronic hepatitis B prevalence among Aboriginal and Torres Strait Islander Australians since universal vaccination: a systematic review and meta-analysis

BACKGROUND

In Australia, higher rates of chronic hepatitis B (HBsAg) have been reported among Aboriginal and Torres Strait Islander (Indigenous) compared with non-Indigenous people. In 2000, the Australian government implemented a universal infant/adolescent hepatitis B vaccination program. We undertook a systematic review and meta-analysis to assess the disparity of HBsAg prevalence between Indigenous and non-Indigenous people, particularly since 2000.

METHODS

We searched Medline, Embase and public health bulletins up to March 2011. We used meta-analysis methods to estimate HBsAg prevalence by Indigenous status and time period (before and since 2000).

RESULTS

There were 15 HBsAg prevalence estimates (from 12 studies) among Indigenous and non-Indigenous people; adults and pregnant women (n = 9), adolescents (n = 3), prisoners (n = 2), and infants (n = 1). Of these, only one subgroup (adults/pregnant women) involved studies before and since 2000 and formed the basis of the meta-analysis. Before 2000, the pooled HBsAg prevalence estimate was 6.47% (95% CI: 4.56-8.39); 16.72% (95%CI: 7.38-26.06) among Indigenous and 0.36% (95%CI:-0.14-0.86) in non-Indigenous adults/pregnant women. Since 2000, the pooled HBsAg prevalence was 2.25% (95% CI: 1.26-3.23); 3.96% (95%CI: 3.15-4.77) among Indigenous and 0.90% (95% CI: 0.53-1.28) in non-Indigenous adults/pregnant women.

CONCLUSIONS

The disparity of HBsAg prevalence between Indigenous and non-Indigenous people has decreased over time; particularly since the HBV vaccination program in 2000. However HBsAg prevalence remains four times higher among Indigenous compared with non-Indigenous people. The findings highlight the need for opportunistic HBV screening of Indigenous people to identify people who would benefit from vaccination or treatment.

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.

Adolescent and young adult HPV vaccination in Australia: achievements and challenges

Australia commenced an ongoing school based government funded human papillomaviruses (HPV) (cervical cancer prevention) vaccination program in April 2007 for adolescent females aged 12-13 years. In addition, up to December 31, 2009, a catch-up program for young females 13-26 years of age was offered: a school-based vaccination program was used to offer HPV vaccine to girls enrolled in school (14-17 years), and general practitioners or other community health provider offered vaccine to young women aged 18-26 years. To date, only the quadrivalent vaccine (HPV 6/11/16/18) has been utilized in the funded program. Acceptance of the vaccine is high with coverage of 3 doses of the HPV vaccine in the school age cohort around 70%, and just over 30% in the older age cohort. Since the vaccination program was initiated, a reduction in new cases of genital warts of 73% among vaccine eligible age females has been evidenced in STI clinics across Australia. A reduction of 44% of new cases in young males (not a part of the free program) was also documented during this same time period, suggesting significant herd immunity. Similarly, in the state of Victoria, a small but significant decrease in high grade abnormalities in Pap screening findings has been reported in young women<18 years for the period 2007-9, as compared to pre-vaccination. Challenges for the future include how we can sustain and improve HPV vaccination coverage in young Australian women, while maintaining cervical cancer screening participation and reviewing cervical cancer screening methods.