Strategies for control and elimination of HBV: modelling and economic evaluation

Abstract

Hepatitis B Virus (HBV) infection continues to be responsible for a large burden of disease globally, and along with the other viral hepatitis infections, ranks amongst the top ten causes of mortality worldwide. This high burden exists despite the availability of safe and effective prevention and treatment tools. This thesis uses applied modelling to answer questions relevant to global public health policy about how these existing interventions can be scaled up, quantify what health gains are achievable and what the economic implications are of alternative strategies of scale-up. Firstly the HBV epidemic is investigated from a global perspective using a dynamic deterministic mathematical model. This shows a decreasing incidence of new infections due to existing prevention efforts taking effect, but that HBV-related deaths will remain high for the next few decades. A comprehensive package of interventions, scaled up to high coverage levels globally, could lead to a 90% reduction in incidence of new chronic infections and avert 7.3 million deaths globally, over the next 15 years compared to status quo. Annual costs of such a strategy are forecast to peak at $7.5bn globally (or $3.4bn in low and middle-income countries only). Next, the dynamic model is used to inform national level strategies in China and Senegal, two countries with high HBV endemicity, but contrasting financial, healthcare and demographic characteristics. Investing in a comprehensive package of prevention and treatment interventions will achieve significant health gains. Furthermore, this approach is likely to provide a return on investment (of 1.54 and 1.72 dollars for every dollar invested, in China and Senegal, respectively), when approached from an overall societal perspective. These economic gains are driven by the reduced costs of management of those with end-stage liver disease and increased productivity gains due to longer life expectancy. These first chapters show that ambitious testing and treatment targets are needed to achieve mortality benefits. The last chapter demonstrates that an active community-based screening and treatment strategy is feasible and likely to be cost-effective in The Gambia, a low-income setting with a high HBV prevalence in West Africa. Overall, these findings demonstrate the substantial health and economic impacts that a concerted effort to combat HBV can achieve on both global and local levels, therefore providing a useful evidence base from which to inform global health policy.