Estimating the annual number of hepatitis C virus infections through vertical transmission at country, regional, and global levels: a data synthesis study.

Abstract

The burden of hepatitis C virus (HCV) among women of childbearing age remains high globally. Studies have estimated that 7-12% of children born to women with HCV infection will acquire HCV, although around two-thirds of children will then clear their HCV infection by 5 years of age. We aimed to estimate the annual number of vertically transmitted HCV infections and how many cases remain at 5 years of age at the country or territory, regional, and global levels. In this data synthesis study, we produced estimates of vertical HCV transmission by combining data from several sources: data on the number of women, age-specific fertility rates, mortality rates among children aged 0-5 years, and HIV prevalence among women aged 15-49 years from the UN; modelled data on HCV prevalence among women aged 15-49 years; meta-analysis data on HCV-HIV co-infection prevalence; and recent estimates of the probabilities of vertical HCV transmission and subsequent clearance by age 5 years. The annual number of births with HCV was estimated by multiplying the number of women with HCV in 5-year age bands by age band-specific birth rates, separately by HIV status, and multiplying by HIV status-specific HCV vertical transmission probabilities. The number of births with HCV was multiplied by the probability of spontaneous clearance of HCV by 5 years of age, accounting for mortality. All estimates were sampled 1000 times from their uncertainty intervals (UIs) to produce 95% UIs. The estimated annual global number of new HCV infections occurring through vertical transmission was 73 862 (95% UI 69 808-78 279). Southern Asia (21 245 [18 095-24 847]), western Africa (16 482 [14 873-18 283]), and eastern Africa (8182 [7479-9085]) were the regions with the most infections. Pakistan (16 350 [13 325-19 844]) and Nigeria (8483 [6944-10 184]) had the largest burden and together accounted for around a third of new infections. We estimated that 23 120 (20 596-25 813) of these children would be alive and still have HCV when aged 5 years. Targeted screening policies that test and treat pregnant women with HCV could prevent substantial numbers of new HCV infections; however, data on the safety of HCV treatments in pregnant women are required. None.