Evaluating Treatment as Prevention Among People Who Inject Drugs in Dundee for HCV
Evaluating Treatment as Prevention Among People Who Inject Drugs in Dundee for HCV
The aim of this study is to conduct an evaluation of hepatitis C treatments in NHS Tayside in
 order to empirically test the "treatment as prevention" models. This will be done by
 analysing the records of patients who have been tested and treated for hepatitis C using NHS
 Tayside databases. There will be no interventions carried out as part of this study.
Hepatitis C is a blood-borne virus (HCV) that can seriously damage the liver and is spread
 mainly through blood-to-blood contact with an infected person. The "serious and significant
 public health risk" posed by HCV was recognised during a member's debate in the Scottish
 Parliament in 2004. By December 2006, Health Protection Scotland estimated that 50,000
 persons in Scotland had been infected with the Hepatitis C virus and that 38,000 were chronic
 carriers. Currently, the greatest risk of acquiring the virus in the UK is through injecting
 drug use. In Scotland, it is estimated that over 85% of individuals who have Hepatitis C were
 infected in this way.

 The outcome of HCV infection varies considerably between individuals. Some (up to 25%) are
 able to clear the infection spontaneously, whilst the remaining 75% become chronically
 infected. Within the subpopulation of chronically infected patients, some will develop
 serious liver disease, including cirrhosis and hepatocellular carcinoma, within a few years,
 whilst in others liver disease will not progress even over a period of more than forty years.
 Hepatitis C is often referred to as the 'silent epidemic.' Many who are infected are unaware
 of it, and often show no symptoms over a long period of time. While there is presently no
 vaccination for Hepatitis C, the recent introduction of protease inhibitor-based directly
 acting anti-viral treatments (DAA) has begun a new era in treatment of this disease. These
 new oral treatments are extremely safe, have shorter treatment regimens than previous drugs,
 and are effective, producing a cure in over 90% of cases providing compliance is adequate.

 The advent of more effective DAA therapies raises the possibility of using therapy as
 prevention, turning the epidemic off at source, by targeting active infected drug users who
 are the main source of new infections.

 The modelling work of the investigators shows that HCV treatment is a critical component to
 HCV prevention among people who inject drugs and is likely to be cost-effective compared to
 delaying treatment or treating non-PWID with mild or moderate disease. For example, the
 investigators show in a number of settings with chronic HCV in PWID below 60% that treating
 10-20 per 1000 drug users per year can reduce HCV prevalence by 50-90% over 10-15 years; that
 for every one PWID treated in the 20% chronic HCV setting 2 new HCV infections are averted.
 The scale of the benefit is inversely and exponentially related to prevalence of HCV in the
 population, the lower the prevalence the sooner and bigger the impact.

 Current conventional treatment pathways focus on populations drawn from those known to drug
 problem services and former drug users. Treating people who are the most stable and with a
 low risk of relapse back into chaotic injecting will reduce future morbidity in the
 individual patients but may not achieve additional benefit in terms of averting future
 infections. The recent work of the investigators within Tayside has shown that they are able
 to test less stable, actively injecting drug users for Hepatitis C and then successfully
 treat them using both the conventional care pathway and non-conventional care pathways, such
 as needle exchange clinics (e.g. Eradicate study, completed February 2017; Advance study,
 aiming to start in October 2017), community pharmacies (SuperDOTC study, ongoing) and
 prisons. If the models are correct, this intensive treatment programme will effectively
 eradicate Hepatitis C from Tayside over the next few years. However, the models are not yet
 empirically tested and they make some assumptions that if violated may lead to over or
 under-estimation of the intervention effect. For example, the models assume that (a)
 heterogeneity in injecting risk and uptake of HCV testing and treatment will even out as PWID
 move and transition between high and low risk periods; and (b) that HCV transmission risk for
 susceptible PWID is similar for those that have achieved SVR or are untreated.

 The intensive treatment approach in Tayside provides an ideal opportunity to empirically test
 the "treatment as prevention" models. The current study will not involve direct recruitment
 or treatment of patients. Instead, it will evaluate the portfolio of care pathways currently
 being used to treat HCV in Tayside and test the hypothetical modelling to determine whether
 treatment of HCV will work as prevention of future spread of the virus.
Inclusion Criteria:

 -  All individuals in NHS Tayside eligible for HCV testing and treatment according to
 Scottish Intercollegiate Guidelines Network guidelines.

 Exclusion Criteria:

 -  None