Identifying the gaps to achieving hepatitis B virus elimination in Africa: the Gambian prolifica experience
File(s)
Author(s)
Ndow, Gibril
Type
Thesis
Abstract
Background and aims
Chronic hepatitis B (CHB) remains a major global health problem. This PhD assessed The Gambia’s progress towards WHO targets for reducing CHB mortality and new infections, identifying gaps and proposing solutions. As the first African country to adopt both infant and birth dose hepatitis B (HepB-BD) vaccinations, The Gambia provides a unique context for assessment.
Methods and results
A prospective cohort analysis (2012-2015) of adults with cirrhosis or hepatocellular carcinoma (HCC) found hepatitis B, C, and Delta seropositivity rates of 84.4%, 9.9%, and 9.9%. Most patients presented with advanced liver disease, with median survival of 17.1months for compensated cirrhosis, 11.3months for decompensated cirrhosis, and 1.5months for HCC. Ascites (HR:1.83) and portal thrombosis (HR:3.81) independently increased mortality among HCC patinets, while Tenofovir treatment improved survival in CHB-related cirrhosis (HR:0.14; p<0.001).
In the population-based PROLIFICA cohort, occult hepatitis B infection (OBI) prevalence was 9.9% in the general population and 18.3% among advanced liver disease patients, and was significantly associated with liver disease (OR:2.8, p=0.006). Among HBsAg-negative people, OBI accounted for 12.9% of advanced liver disease cases.
Among HIV patients, HBV screening was low (21.5%) and only 26.1% of HIV-HBV co-infected patients received appropriate treatment. Co-infected patients had higher APRI scores with 98.1% (52/53) having detectable HBV DNA and 83.3% (10/12) had 3TC-resistance mutations linked to increased liver fibrosis (p=0.05).
Timely HepB-BD coverage in rural Gambia rose from 1.8% (2015) to 20.7% (2021). Births in health facilities (OR:0.76) and maternal education (OR:0.50) increased timely HepB-BD, while delays were associated with remote regions (OR:1.96), weekend births (OR:6.14), or increasing maternal age (OR:1.008 for every additional year). Timely vaccination declined from 10.1% pre-COVID to 5.4% during the first wave.
Summary
Despite progress, gaps in disease prevention, screening, and treatment remain. Integrated, resource-efficient strategies are needed to meet WHO elimination targets by 2030.
Chronic hepatitis B (CHB) remains a major global health problem. This PhD assessed The Gambia’s progress towards WHO targets for reducing CHB mortality and new infections, identifying gaps and proposing solutions. As the first African country to adopt both infant and birth dose hepatitis B (HepB-BD) vaccinations, The Gambia provides a unique context for assessment.
Methods and results
A prospective cohort analysis (2012-2015) of adults with cirrhosis or hepatocellular carcinoma (HCC) found hepatitis B, C, and Delta seropositivity rates of 84.4%, 9.9%, and 9.9%. Most patients presented with advanced liver disease, with median survival of 17.1months for compensated cirrhosis, 11.3months for decompensated cirrhosis, and 1.5months for HCC. Ascites (HR:1.83) and portal thrombosis (HR:3.81) independently increased mortality among HCC patinets, while Tenofovir treatment improved survival in CHB-related cirrhosis (HR:0.14; p<0.001).
In the population-based PROLIFICA cohort, occult hepatitis B infection (OBI) prevalence was 9.9% in the general population and 18.3% among advanced liver disease patients, and was significantly associated with liver disease (OR:2.8, p=0.006). Among HBsAg-negative people, OBI accounted for 12.9% of advanced liver disease cases.
Among HIV patients, HBV screening was low (21.5%) and only 26.1% of HIV-HBV co-infected patients received appropriate treatment. Co-infected patients had higher APRI scores with 98.1% (52/53) having detectable HBV DNA and 83.3% (10/12) had 3TC-resistance mutations linked to increased liver fibrosis (p=0.05).
Timely HepB-BD coverage in rural Gambia rose from 1.8% (2015) to 20.7% (2021). Births in health facilities (OR:0.76) and maternal education (OR:0.50) increased timely HepB-BD, while delays were associated with remote regions (OR:1.96), weekend births (OR:6.14), or increasing maternal age (OR:1.008 for every additional year). Timely vaccination declined from 10.1% pre-COVID to 5.4% during the first wave.
Summary
Despite progress, gaps in disease prevention, screening, and treatment remain. Integrated, resource-efficient strategies are needed to meet WHO elimination targets by 2030.
Version
Open Access
Date Issued
2022-11-04
Date Awarded
2025-01-01
Copyright Statement
Attribution-NonCommercial 4.0 International Licence (CC BY-NC)
License URL
Advisor
Thursz, Mark R
Lemoine, Maud
Shimakawa, Yusuke
Publisher Department
Department of Metabolism, Digestion and Reproduction
Publisher Institution
Imperial College London
Qualification Level
Doctoral
Qualification Name
Doctor of Philosophy (PhD)