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Abstract Details
Hepatitis B Virus Seroepidemiology Data for Africa: Modelling Intervention Strategies Based on a Systematic Review and Meta-Analysis
Anna L McNaughton1, José Lourenço2, Phillip Armand Bester3, Jolynne Mokaya1, Sheila F Lumley14, Uri Obolski56, Donall Forde7, Tongai G Maponga8, Kenneth R Katumba9, Dominique Goedhals3, Sunetra Gupta2, Janet Seeley910, Robert Newton911, Ponsiano Ocama12, Philippa C Matthews14
Author information
1Nuffield Department of Medicine, University of Oxford, Medawar Building for Pathogen Research, Oxford, United Kingdom.
2Department of Zoology, University of Oxford, Medawar Building for Pathogen Research, Oxford, United Kingdom.
3Division of Virology, University of the Free State and National Health Laboratory Service, Bloemfontein, South Africa.
4Department of Infectious Diseases and Microbiology, Oxford University Hospitals NHS Foundation Trust, John Radcliffe Hospital, Headington, Oxford, United Kingdom.
5School of Public Health, Tel Aviv University, Tel Aviv, Israel.
6Porter School of the Environment and Earth Sciences, Tel Aviv University, Tel Aviv, Israel.
7Nuffield Department of Medicine, Nuffield Department of Medicine Research Building, Headington, Oxford, United Kingdom.
8Division of Medical Virology, University of Stellenbosch, Faculty of Medicine and Health Sciences, Cape Town, South Africa.
9Medical Research Council/Uganda Virus Research Institute and London School of Hygiene and Tropical Medicine Uganda Research Unit, Entebbe, Uganda.
10Faculty of Global Health and Development, London School of Hygiene and Tropical Medicine, London, United Kingdom.
11Department of Health Sciences, University of York, York, United Kingdom.
12Makerere University College of Health Sciences, Kampala, Uganda.
Abstract
Background: International Sustainable Development Goals (SDGs) for elimination of hepatitis B virus (HBV) infection set ambitious targets for 2030. In African populations, infant immunisation has been fundamental to reducing incident infections in children, but overall population prevalence of chronic hepatitis B (CHB) infection remains high. In high-prevalence populations, adult catch-up vaccination has sometimes been deployed, but an alternative Test and Treat (T&T) approach could be used as an intervention to interrupt transmission. Universal T&T has not been previously evaluated as a population intervention for HBV infection, despite high-profile data supporting its success with human immunodeficiency virus (HIV).
Methods and findings: We set out to investigate the relationship between prevalence of HBV infection and exposure in Africa, undertaking a systematic literature review in November 2019. We identified published seroepidemiology data representing the period 1995-2019 from PubMed and Web of Science, including studies of adults that reported prevalence of both hepatitis B surface antigen (HBsAg; prevalence of HBV infection) and antibody to hepatitis B core antigen (anti-HBc; prevalence of HBV exposure). We identified 96 studies representing 39 African countries, with a median cohort size of 370 participants and a median participant age of 34 years. Using weighted linear regression analysis, we found a strong relationship between the prevalence of infection (HBsAg) and exposure (anti-HBc) (R2 = 0.45, p < 0.001). Region-specific differences were present, with estimated CHB prevalence in Northern Africa typically 30% to 40% lower (p = 0.007) than in Southern Africa for statistically similar exposure rates, demonstrating the need for intervention strategies to be tailored to individual settings. We applied a previously published mathematical model to investigate the effect of interventions in a high-prevalence setting. The most marked and sustained impact was projected with a T&T strategy, with a predicted reduction of 33% prevalence by 20 years (95% CI 30%-37%) and 62% at 50 years (95% CI 57%-68%), followed by routine neonatal vaccination and prevention of mother to child transmission (PMTCT; at 100% coverage). In contrast, the impact of catch-up vaccination in adults had a negligible and transient effect on population prevalence. The study is constrained by gaps in the published data, such that we could not model the impact of antiviral therapy based on stratification by specific clinical criteria and our model framework does not include explicit age-specific or risk-group assumptions regarding force of transmission.
Conclusions: The unique data set collected in this study highlights how regional epidemiology data for HBV can provide insights into patterns of transmission, and it provides an evidence base for future quantitative research into the most effective local interventions. In combination with robust neonatal immunisation programmes, ongoing PMTCT efforts, and the vaccination of high-risk groups, diagnosing and treating HBV infection is likely to be of most impact in driving advances towards elimination targets at a population level.