Epidemiology and Risk Factors for HCV Infection in MSM With or at Risk of HIV in Madrid

Overview

This prospective study (2022–2024) in Madrid assessed hepatitis C virus (HCV) prevalence, incidence, and risk factors among men who have sex with men (MSM) with HIV and those on pre-exposure prophylaxis (PrEP). Findings revealed higher baseline HCV prevalence and incidence among MSM with prior HCV exposure, with risky sexual behaviors such as slamsex and condomless receptive anal intercourse with multiple partners strongly associated with infection and reinfection.

Background

Hepatitis C virus (HCV) transmission historically linked to blood transfusions and injection drug use has increasingly involved high-risk sexual behaviors among MSM, especially those with HIV or on PrEP. Despite advances in direct-acting antiviral (DAA) therapies achieving high cure rates, ongoing transmission and reinfection challenge elimination efforts. Understanding local epidemiology and behavioral risk factors is critical to inform targeted prevention strategies in this population.

Data Highlights

Key Findings

• Baseline HCV prevalence was significantly higher in MSM with prior HCV exposure (5.60%) compared to those without (0.72%), with a prevalence ratio of 7.72 (95% CI: 3.31–18.03).
• Overall HCV incidence was 1.45 per 100 person-years, with primary infection incidence higher in PrEP users (0.94/100 PY) than MSM with HIV (0.65/100 PY), though not statistically significant (IRR 1.44, 95% CI: 0.24–9.80).
• HCV reinfection incidence was markedly elevated at 4.32 per 100 PY overall, particularly among PrEP users (12.90/100 PY) compared to MSM with HIV (4.05/100 PY), IRR 3.21 (95% CI: 0.07–22.53).
• Two participants experienced reinfection within the study period, corresponding to an incidence of 8.7 per 100 PY (95% CI: 1.05–31.4).
• Independent behavioral risk factors for HCV infection and reinfection included slamsex (injection drug use in sexual contexts) and condomless receptive anal intercourse with four or more partners.
• MSM with prior HCV exposure had consistently higher prevalence and incidence rates regardless of HIV status, underscoring the importance of prior infection history.

Clinical Implications

Clinicians should recognize that MSM engaging in high-risk sexual behaviors, particularly slamsex and condomless receptive anal intercourse with multiple partners, remain at elevated risk for HCV infection and reinfection. Regular HCV screening and behavioral risk assessments are essential, especially for MSM on PrEP and those with prior HCV exposure. Integrating behavior-informed prevention strategies alongside DAA treatment is critical to sustain HCV elimination efforts in this population.

Conclusion

Despite broad access to effective DAA therapies, ongoing high-risk behaviors among MSM with or at risk for HIV continue to drive HCV transmission and reinfection in Madrid. Targeted prevention and continuous epidemiological monitoring are vital to achieving HCV elimination goals in this key population.

References

1. Epidemiological Insights and Risk Factors for HCV Infection in MSM With or Susceptible to HIV in Madrid (2022–2024)