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

Background

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.

Methods

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.

Findings

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.

Interpretation

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.

Funding

None.