Estimating the Remaining Chronic HCV Prevalence in Ireland: A Risk Population Modelled Approach Applied in Practice

OBJECTIVES: The WHO set a timeline of 2030 to achieve elimination of viral hepatitis. A recent publication by McCormick et al estimated HCV prevalence to be ~0.09% in the Irish population. High rates of HCV infection are still detected in high-risk populations (e.g. homeless, substance misuse, prisons). Aim of this analysis was to understand recent HCV prevalence in context of high-risk populations, providing an inclusive, bottom-up calculation of chronic HCV prevalence across Ireland.

METHODS: Systematic literature review was conducted to find relevant published data regarding HCV prevalence in key risk groups in Ireland. Data was extracted from relevant publications, meta-analysis performed to generate weighted prevalence rates of HCV for each risk group. McCormick et al was used for low-risk populations. General population, homeless, prisons and substance misuse populations in Ireland were used to size risk groups in each HSE area. Populations were divided into high or low-risk with relevant HCV rates applied.

RESULTS: This methodology generated a prevalence of HCV in Ireland of 10.3k, a restated prevalence rate of 0.23%. This was comprised of 3.8k substance misuse patients (28% prevalence), 2k homeless patients (27%), 0.7k in prisons (15%) and 3.8k in the remaining low-risk general population (0.09%). Approximately half of the calculated HCV prevalence (5.1k) was in HSE East region (Dublin, Kildare & Wicklow).

CONCLUSIONS: Remaining prevalence of HCV in Ireland is likely higher than recently published rates. Estimates for HCV in Ireland were previously stated at 20-50k by the HSE (2014). Approximately 8.3k patients have received direct acting ARV curative treatment. This would indicate that at least 10k patients could be at risk in Ireland. A community rate of 0.09% is unlikely to represent the remaining prevalence of HCV in Ireland.