Fitting a programmatic response to the hepatitis B virus epidemic in sub-Saharan Africa in the era of elimination
File(s)
Author(s)
Schmit, Nora
Type
Thesis
Abstract
Chronic hepatitis B virus (HBV) infection is an important cause of liver cancer and cirrhosis and has a particularly high burden in sub-Saharan Africa, where access to treatment and prevention interventions against mother-to-child transmission remains limited. This thesis uses mathematical modelling to analyse the HBV epidemic and potential strategies for implementation of screening and treatment in a sub-Saharan African setting. Firstly, existing evidence on the HBV epidemic in sub-Saharan Africa is reviewed by both comparing different sets of modelled HBV prevalence estimates and conducting a scoping review of the published literature on HBV epidemiology and natural history. Data gaps on the chronic infection prevalence in children, burden of cirrhosis and contribution of mother-to-child transmission to new infections in the post-vaccination era are identified. Next, a dynamic model of HBV transmission is developed based on an existing framework and adapted to the sub-Saharan African context. Synthesising all available data from The Gambia in a Bayesian framework further reveals key uncertainties in natural history model parameters. Projections suggest that HBV elimination as a public health threat would be possible in The Gambia by 2030 with full scale-up of all available interventions, depending on the targets used to define it. Lastly, the model is used to investigate the population-level impact and cost-effectiveness of introducing screening and treatment in The Gambia, including different strategies for monitoring treatment-ineligible chronic carriers, targeting different segments of the population and repeated screening over time. The analysis shows that just a one-time population-based screening and treatment programme could substantially reduce HBV-related mortality in the Gambian population, and would be cost-effective if monitoring is reduced from the currently recommended annual frequency to every 5 years in under 45-year-olds. Overall, findings from this thesis provide guidance to policymakers on locally relevant strategies for implementation of treatment programmes in sub-Saharan Africa in the era of elimination, as well as an evidence base to inform further HBV modelling studies.
Version
Open Access
Date Issued
2021-07
Date Awarded
2021-11
Copyright Statement
Creative Commons Attribution NonCommercial Licence
License URL
Advisor
Hallett, Timothy
Publisher Department
Infectious Disease Epidemiology
Publisher Institution
Imperial College London
Qualification Level
Doctoral
Qualification Name
Doctor of Philosophy (PhD)