Global prevalence of hepatitis C virus in women of childbearing age in 2019: a modelling study.

BACKGROUND: Treatment for infection with hepatitis C virus (HCV) during pregnancy has not yet been approved; however, interventions specifically targeting women, especially those of childbearing age (15-49 years), could prevent vertical transmission and community spread. To assess the impact of such interventions, improved prevalence estimates in this group are needed. We aimed to estimate the global prevalence of viraemic HCV in 2019 among women of childbearing age. METHODS: In this modelling study, we used previously developed models for 110 countries inputted with country-specific demographic and HCV epidemiology data. We did a literature review, searching PubMed, Embase, and grey literature for studies published between Jan 1, 2000, and June 30, 2018, reporting HCV antibody or viraemic prevalence in women of childbearing age. Studies from the literature review and studies in models were compared by use of a data quality scoring system and models were updated, as appropriate, when a better study was identified. We used these HCV disease burden models to calculate the 2019 prevalence of viraemic HCV in women of childbearing age. In countries without a model, prevalence was extrapolated by Global Burden of Disease (GBD) region. FINDINGS: An estimated 14 860 000 (95% uncertainty interval [UI] 9 667 000-18 282 000) women aged 15-49 years had HCV infection worldwide in 2019, corresponding to a viraemic prevalence of 0·78% (95% UI 0·62-0·86). Globally, HCV prevalence increased with age, rising from 0·25% (95% UI 0·20-0·27) in women aged 15-19 years to 1·21% (0·97-1·34) in women aged 45-49 years. China (16% of total infections) and Pakistan (15%) had the greatest numbers of viraemic infections, but viraemic prevalence was highest in Mongolia (5·14%, 95% CI 3·46-6·28) and Burundi (4·91%, 3·80-18·75). Of the countries with 500 cases or more, viraemic prevalence was lowest in Chile (0·07%, 95% UI 0·04-0·12). Among the GBD regions, eastern Europe had the highest viraemic prevalence (3·39%, 95% UI 1·88-3·54). By WHO region, the Eastern Mediterranean region had the highest viraemic prevalence (1·75%, 95% UI 1·26- 1·90). INTERPRETATION: Most research on HCV disease burden among women aged 15-49 years focuses on pregnant women. Using modelling, this analysis provides global and national estimates of HCV prevalence in all women of childbearing age. These data can inform preconception test-and-treat strategies to reduce vertical transmission and total disease burden. FUNDING: Gilead Sciences, John C Martin Foundation, private donors.

Global prevalence of hepatitis C virus in children in 2018: a modelling study.

BACKGROUND: Hepatitis C virus (HCV) prevalence estimates for adults and high-risk groups have been widely published, but the disease burden in children is poorly understood. Direct-acting antiviral drugs, which are considered to be highly effective curative therapies for HCV, are now approved for paediatric patients as young as 3 years. Reliable prevalence estimates for this population are needed to inform scale-up of treatment and national strategies. This analysis combines past modelling and epidemiological work in 104 countries and territories to estimate global HCV prevalence in children in 2018. METHODS: In this modelling study, a comprehensive literature review for articles published between Jan 1, 2000, and March 31, 2019, was used to determine historical HCV prevalence estimates in children in all 249 countries and territories of the world. We identified published HCV prevalence estimates for children aged 0-18 years who are not at high risk of HCV infection in 39 countries and territories and inputted them into dynamic Markov disease-burden models to estimate viraemic HCV prevalence in 2018. For 25 of them, which had complete data, available information on HCV prevalence in children was used to build regression models to predict paediatric prevalence in an additional 65 countries and territories that had country-specific or territory-specific data about predictors only. Regression models were created for each 5-year paediatric age cohort from 0 to 19 years, considering several predictor variables. The data and forecasts from the 104 countries and territories for which data were available were used to calculate HCV prevalence by Global Burden of Disease region, which was then applied to the remaining 145 countries and territories to generate a global estimate. FINDINGS: The global estimate for viraemic prevalence in the paediatric population aged 0-18 years was 0·13% (95% uncertainty interval 0·08-0·16), corresponding to 3·26 million (2·07-3·90) children with HCV in 2018. HCV prevalence increased with age in all countries and territories. HCV prevalence in women of childbearing age was the strongest predictor of HCV prevalence in children aged 0-4 years (p<0·0001). Prevalence of HCV in adults was significantly associated with HCV prevalence in children aged 5-19 years (p<0·0001), and the proportion of HCV infections in people who inject drugs was significantly associated with HCV prevalence in children aged 15-19 years (p=0·036). INTERPRETATION: Most studies on HCV prevalence in children focus on high-risk groups and highly endemic geographic areas. Our analysis provides global prevalence estimates of HCV in the paediatric population. Treatment in paediatric patients requires different clinical and population health management optimisation than in adults. Because of this heterogeneity, country-specific or territory-specific and age-specific HCV prevalence estimates can help countries and territories to improve national HCV elimination strategies. FUNDING: Gilead Sciences, John C Martin Foundation, and private donors.