Early evidance of the impact of scaling up provision of direct-acting antivirals for hepatitis C on the chronic prevalence among people who inject drugs in England: real world data, 2011-2018
Direct-acting antivirals (DAAs) for the treatment of Hepatitis C virus (HCV) have been scaled up in the UK since 2015. Investigating the impact of DAAs on chronic HCV prevalence among the key affected population of people who inject drugs (PWID) is one aim of the EPIToPE study (Evaluating the Population Impact of Hepatitis C Direct Acting Antiviral Treatment as Prevention for People Who Inject Drugs). As part of EPIToPE, trends in chronic HCV prevalence and treatment status among PWID over time (including years in the pre-DAA era and post-DAA era) were examined.
Questionnaire data and virological results from the unlinked-anonymous monitoring survey of PWID in England from 2011, 2014 and 2016-2018 were analysed. Temporal changes in the proportion chronically infected (HCV RNA positive) among those ever infected (HCV antibody positive) were examined in a multivariable model, with geographical region, gender, age and injecting status in the past year treated a priori as confounders. Additionally, the proportion who self-reported ever receiving HCV treatment among those who had cleared infection (HCV antibody positive, HCV RNA negative) was explored.
Of 2,211 survey participants in 2011, 906 (41.0%) were ever infected, over half of whom (58.2%) were chronically infected. The proportion chronically infected among those ever infected was similar in 2014 (56.8%; 663/1,167, p=0.54) and 2016 (55.9%; 612/1,095, p=0.31), but fell to 49.7% in 2017 (584/1,174, p<0.001) and 49.5% in 2018 (645/1,304, p<0.001).
After adjustment, year was significantly associated with chronic infection (p<0.001), with a decrease from 2011 levels observed in both 2017 (aOR 0.72, 95%CI 0.60-0.87, p=0.001) and 2018 (aOR 0.71, 95%CI 0.59-0.85, p<0.001). Other factors associated with chronic infection in multivariate analysis were gender (female aOR 0.67, 95%CI 0.59-0.76), injecting in the past year (aOR 1.20, 95%CI 1.05-1.37, p=0.01) and history of homelessness (aOR 1.20, 95%CI 1.04-1.39, p=0.01), with weak evidence of an association with history of imprisonment (aOR 1.13, 95%CI 0.99-1.30, p=0.08).
Among those with cleared infection and for whom treatment evidence was available, the proportion of participants who reported ever receiving HCV treatment increased over time (p<0.001), most notably in the post-DAA era (2011, 21% [74/352]; 2014, 11% [48/449]; 2016, 15% [68/452]; 2017, 30% [138/464]; 2018, 38% [213/555]).
These are the first data on chronic HCV among PWID over time in England, and show a small recent reduction in HCV infection concomitant with the scale-up of DAA treatment among PWID. The odds of chronic infection among those ever infected in 2017 and 2018 were less than three-quarters that in 2011. Furthermore, the proportion of PWID with cleared HCV infection reporting ever receiving treatment for their HCV is at its highest level so far in 2018, indicating access to care pathways has improved with the scale-up of DAA treatment. Monitoring at the population level is critical for the continued evaluation of HCV treatment as prevention, and despite these initial positive results considerable treatment scale-up is required in order for England to meet the World Health Organisation elimination targets.