Hepatitis D: not a rare disease anymore: global update for 2017–2018

We sincerely appreciate Stockdale and colleagues1 for their critical consideration of our article. Herein, we tried to answer their concerns about the methodology of our meta-analysis.2 We used hepatitis D virus (HDV) antibody (both IgM and IgG) seropositivity as a measure of overall burden of HDV seroprevalence. Although anti-HDV IgM Ab assays may fail to detect low titres of antibodies and underestimate HDV seroprevalence,3 patients with a negative anti-HDV IgM results are less likely to progress into clinical disease.4 Majority of the included studies in our article used anti-HDV antibody assays and only two mentioned the use of RNA assays for the prevalence of HDV. Therefore, considering the wide application of the anti-HDV antibody assay as a measure of HDV seroprevalence,5 we used the similar method in our meta-analysis. We do not think it would be correct to extrapolate the prevalence of HBsAg based on our estimates of HDV seroprevalence among general population and mixed population (HBsAg carriers without risk factors such as intravenous drug use and high-risk sexual behaviours). This is because the general population and the mixed …