Abstract
Chronic liver disease is an under-diagnosed but increasing cause of premature morbidity and mortality in Africa, driven predominantly by chronic hepatitis B virus (HBV) infection and hazardous alcohol consumption (HAC). This thesis aims to describe the prevalence and determinants of HBV and HAC in Malawi, to assess the associated burden of liver fibrosis and cirrhosis, to evaluate the performance of non-invasive diagnostic tools, and to explore new public health approaches to prevent, detect and manage liver disease in a low-resource setting.A systematic review and meta-analysis of HBV epidemiology in pregnant women in Africa was conducted to estimate pooled prevalence and vertical transmission risk associated with different preventative interventions, and how these have changed over time. This confirmed a higher risk of infection in pregnant women, with considerable regional variation, and identified vertical transmission as an important ongoing source of infection. Modelling future trends identified that, without scale-up of an HBV birth-dose vaccine and strengthening maternal antiviral prophylaxis delivery, HBV prevalence in Africa will remain persistently high over the next two decades.
A large community-based serosurvey of more than 4,300 adults across rural Karonga and urban Lilongwe provided robust population-level prevalence estimates of HBV in Malawi. Overall prevalence was 4.3% (95% CrI 3.6-5.0) in Karonga and 3.5% (95% CrI 2.6-4.8) in Lilongwe, equivalent to approximately 357,000 Malawian adults living with chronic HBV infection. Prevalence was higher in men than women (OR 1.6 (95% CrI 1.2-2.1)), peaked in mid-adulthood, and had limited association with HIV prevalence. Most individuals were unaware of their infection, highlighting the critical importance of scaling up active case finding to identify people with undiagnosed disease.
In parallel, an alcohol survey of more than 15,000 adults identified high levels of self-reported HAC based on AUDIT scores, with prevalence of 11.9% (95% CrI 11.0-12.8) in Lilongwe and 8.6% (95% CrI 7.9-9.3) in Karonga. Almost one in four men met the threshold for HAC compared with fewer than 2% of women, although women who did drink appeared to represent a particularly vulnerable group, with strong associations observed with HIV-positivity, social isolation, and alcohol outlet density. Short-form AUDIT-C screening performed well in men but less effectively in women due to their low prevalence of HAC.
A clinical assessment of over 350 individuals with HBV or HAC identified by these surveys demonstrated that significant liver fibrosis or cirrhosis was already present in 19.3% of those with HBV and 14.4% of hazardous drinkers. 32.6% of men with HBV also reported hazardous alcohol consumption. Diagnostic biomarkers such as APRI, FIB-4, GPR and TREAT-B showed poor diagnostic accuracy performance in detecting people with liver fibrosis and cirrhosis compared to transient elastography results. Eight individuals with HBV were started on antiviral treatment, with follow-up confirming improvements in viral load and liver stiffness.
The findings from this thesis show that in Malawi, HBV and HAC are major overlapping epidemics, driving liver morbidity in adults, and often from a young age. Strengthening HBV prevention, widening access to screening and treatment, and integrating alcohol reduction approaches into broader health programmes are required urgently to reduce the rising burden of liver disease in Africa.
| Date of Award | 14 Jan 2026 |
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| Original language | English |
| Awarding Institution |
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| Supervisor | Peter MacPherson (Supervisor), Marc Henrion (Supervisor), Amelia C. Crampin (Supervisor) & Alexander Stockdale (Supervisor) |
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