What is needed to achieve HCV microelimination among HIV-infected populations in Andalusia, Spain: a modeling analysis.

Background: Scale-up of hepatitis C virus (HCV) treatment for HIV/HCV coinfected individuals is occurring in Spain, the vast majority (> 85%) with a reported history of injecting drug use and a smaller population of co-infected men who have sex with men (MSM). We assess impact of recent treatment scale-up to people living with HIV (PLWH) and implications for achieving the WHO HCV incidence elimination target (80% reduction 2015-2030) among PLWH and overall in Andalusia, Spain, using dynamic modeling.

Methods: A dynamic transmission model of HCV/HIV coinfection was developed. The model was stratified by people who inject drugs (PWID) and MSM. The PWID component included dynamic HCV transmission from the HCV-monoinfected population. The model was calibrated to Andalusia based on published data and the HERACLES cohort (prospective cohort of HIV/HCV coinfected individuals representing > 99% coinfected individuals in care in Andalusia). From HERACLES, we incorporated HCV treatment among diagnosed PLWH of 10.5%/year from 2004 to 2014, and DAAs at 33%/year from 2015 with 94.8% SVR. We project the impact of current and scaled-up HCV treatment for PLWH on HCV prevalence and incidence among PLWH and overall.

Results: Current treatment rates among PLWH (scaled-up since 2015) could substantially reduce the number of diagnosed coinfected individuals (mean 76% relative reduction from 2015 to 2030), but have little impact on new diagnosed coinfections (12% relative reduction). However, DAA scale-up to PWLH in 2015 would have minimal future impact on new diagnosed coinfections (mean 9% relative decrease from 2015 to 2030). Similarly, new cases of HCV would only reduce by a mean relative 29% among all PWID and MSM due to ongoing infection/reinfection. Diagnosing/treating all PLWH annually from 2020 would increase the number of new HCV infections among PWLH by 28% and reduce the number of new HCV infections by 39% among the broader population by 2030.

Conclusion: Targeted scale-up of HCV treatment to PLWH can dramatically reduce prevalence among this group but will likely have little impact on the annual number of newly diagnosed HIV/HCV coinfections. HCV microelimination efforts among PWLH in Andalusia and settings where a large proportion of PLWH have a history of injecting drug use will require scaled-up HCV diagnosis and treatment among PLWH and the broader population at risk.