Epidemiological data for hepatitis D in Africa – Authors' reply
Authors: Alexander J Stockdale, Apostolos Beloukas, Anna Maria Geretti
Journal: The Lancet Global Health (2017)

Jose Debes and Shemal Shah highlight the paucity of data from east Africa, one of our major findings. The authors draw attention to a study from Tanzania, where samples that initially tested positive for antibodies against hepatitis D virus by a commercial assay did not test positive on retesting with a second assay.1Winter A Letang E Vedastus Kalinjuma A et al.Absence of hepatitis delta infection in a large rural HIV cohort in Tanzania.Int J Infect Dis. 2016; 46: 8-10Summary Full Text Full Text PDF PubMed Scopus (17) Google Scholar The performance of the second assay relative to the first was unknown. Given that the first assay was used widely in the studies included in our analysis without confirmation by a second assay, we elected not to take retesting into account for the study from Tanzania and to maintain consistency with data available from the other studies. Further research is required to determine whether there is a generalisable issue with the specificity of hepatitis D virus antibody testing in Africa. We agree that considerations of assay specificity are important in this setting, as also seen with the detection of antibodies against hepatitis C virus.2King S Adjei-Asante K Appiah L et al.Antibody screening tests variably overestimate the prevalence of hepatitis C virus infection among HIV-infected adults in Ghana.J Viral Hepat. 2015; 22: 461-468Crossref PubMed Scopus (15) Google Scholar In the case of hepatitis B virus testing, however, there appears to be an issue of reduced sensitivity, rather than reduced specificity, when using rapid screening tests for HBsAg.3Geretti AM Patel M Sarfo FS et al.Detection of highly prevalent hepatitis B virus coinfection among HIV-seropositive persons in Ghana.J Clin Microbiol. 2010; 48: 3223-3230Crossref PubMed Scopus (73) Google Scholar We are less clear about the assertion that suppression of hepatitis B virus replication with antiviral therapy makes hepatitis D virus positivity less likely. The hepatitis D virus particle comprises an RNA genome, a single hepatitis D virus-encoded antigen, and a lipoprotein envelope provided by hepatitis B virus. Nucleoside and nucleotide analogues inhibit replication of hepatitis B virus, but rarely lead to HBsAg loss. Although long-term suppression of hepatitis B virus replication might possibly also result in the suppression of hepatitis D virus replication, evidence in support of this statement is at best conflicting.4Soriano V Vispo E Sierra-Enguita R et al.Efficacy of prolonged tenofovir therapy on hepatitis delta in HIV-infected patients.AIDS. 2014; 28: 2389-2394Crossref PubMed Scopus (51) Google Scholar, 5Béguelin C Friolet N Moradpour D et al.Impact of tenofovir on hepatitis delta virus replication in the Swiss HIV cohort study.Clin Infect Dis. 2017; 64: 1275-1278Crossref PubMed Scopus (18) Google Scholar It is nonetheless important to emphasise that eradication of hepatitis D virus at the population level must ultimately rely on the implementation of effective policies to reduce hepatitis B virus transmission. Edouard Tuaillon and colleagues describe the use of dried blood spots (DBSs) for the detection of antibodies against hepatitis D virus in a large survey of adult volunteers in Burkina Faso. Consistent with our conclusions,6Stockdale AJ Chaponda M Beloukas A et al.Prevalence of hepatitis D virus infection in sub-Saharan Africa: a systematic review and meta-analysis.Lancet Glob Health. 2017; 5: e992-e1003Summary Full Text Full Text PDF PubMed Scopus (76) Google Scholar the authors observed localised clusters of endemicity, and exploration of the risk factors for hepatitis D virus infection in the same population would be of interest. The report indicates that DBS offer a promising tool for obtaining representative measurements of the prevalence of hepatitis D virus. Validation data will increase confidence in the reliability of DBS testing for antibodies against hepatitis D virus. Important technical challenges remain: use of elutes from DBS samples reduces overall testing sensitivity, and whether DBS testing is a suitable method for hepatitis D virus RNA detection in Africa remains to be demonstrated. This online publication has been corrected. The corrected version first appeared at thelancet.com/lancetgh on January 15, 2018 This online publication has been corrected. The corrected version first appeared at thelancet.com/lancetgh on January 15, 2018 AMG reports consultancy and speaker fees from Abbott, AbbVie, Bristol-Myers Squibb, Gilead, Janssen, and ViiV. The University of Liverpool is the recipient of research funds from Bristol-Myers Squibb, Gilead, Janssen, and ViiV for studies of which AMG is the principal investigator. AMG is employed as an expert scientist by Roche Pharma Research and Early Discovery (pRED); Roche pRED has no involvement in the work presented. All other authors declare no competing interests. Prevalence of hepatitis D virus infection in sub-Saharan Africa: a systematic review and meta-analysisFindings suggest localised clusters of hepatitis D virus endemicity across sub-Saharan Africa. Epidemiological data are needed from southern and east Africa, and from patients with established liver disease. Further studies should aim to define the reliability of hepatitis D virus testing methods, identify risk factors for transmission, and characterise the natural history of the infection in the region. Full-Text PDF Open AccessEpidemiological data for hepatitis D in AfricaThe systematic review on the seroprevalence of hepatitis D virus in sub-Saharan Africa by Alexander Stockdale and colleagues1 is a key contribution to the epidemiology of hepatitis D virus infection, and highlights the scarcity of reliable data from the African continent. Most of the studies included in this meta-analysis were based on convenience sampling, and less than half of these studies include a confirmation of hepatitis D virus infection by a molecular test. The Article concludes that there is a need for reliable epidemiological data that are representative of the general population, that there are localised clusters of hepatitis D virus endemicity, and that there is a need for reliable hepatitis D virus testing methods. Full-Text PDF Open AccessEpidemiological data for hepatitis D in AfricaAlexander Stockdale and colleagues (October, 2017)1 describe the epidemiology of hepatitis D virus in Africa, and conclude that the infection is more common in west Africa than in other regions, particularly east Africa. This epidemiological statement is generally known among practising hepatologists and has important implications when screening for hepatitis D virus. However, a few points should be highlighted from the study. Full-Text PDF Open AccessCorrection to Lancet Glob Health 2018; 6: e34Stockdale AJ, Beloukas A, Geretti AM. Epidemiological data for hepatitis D in Africa. Author's reply. Lancet Glob Health 2018; 6: e34—In this Correspondence (January, 2017), Anna Maria Geretti's name was misspelled. This correction has been made as of Jan 15, 2018. Full-Text PDF Open Access