Hepatitis C virus (HCV) is a major cause of liver disease worldwide. Globally, an estimated 80 million people have chronic HCV infection.¹ In Ireland there are between 20,100 and 42,000 people with HCV infection, 60% of whom are as yet undiagnosed.^2,3,4 Between 55-85% of people infected go on to develop chronic infection, and between 15%-30% of those will develop cirrhosis, approximately 20 years after infection.¹ HCV infection is sometimes called the ‘silent killer’ because symptoms usually don’t develop until liver disease is already advanced. It is also called silent because many of those infected or most at risk of infection are marginalised in society. 

In recent years there have been major advancements in the treatment of HCV. Treatment with direct-acting antiretrovirals (DAAs) is now the standard of care.^1,5 DAAs are highly effective, and are associated with virological cure rates of over 90%. Access to treatment in Ireland has been introduced through the HSE National Hepatitis C Treatment Programme (NHCTP) on a phased basis based on clinical criteria, with those having greatest clinical need receiving treatment initially. 

Criteria for access to treatment are continually expanding. The NHCTP is aiming to provide treatment across a range of healthcare settings to all persons living with HCV in Ireland over the coming years.⁶ To date, since 2015 just over 2,000 people have been provided with treatment as part of the national programme. The availability of drugs that can effectively cure HCV means that screening for HCV is now more important than ever. 

Globally, the availability of DAAs has shifted the focus towards elimination of HCV. In 2016 the World Health Organization (WHO) set a goal of eliminating viral hepatitis as a major public health threat by 2030.⁷ WHO has stated that national testing policies are needed, as are increased investments in HCV screening services, so that the goal of elimination can be reached.

Screening in Ireland

In Ireland, screening for HCV infection takes place in many settings, including in general practice. However, until now national guidelines on who should be screened and in what settings this should happen were not available. The need for national screening guidelines was recognised by the National Hepatitis C Strategy⁸ and, in response to their recommendation, a National Clinical Guideline on Hepatitis C Screening was developed to make recommendations on who should be screened for HCV and how that screening should be done.⁹ The guideline was developed under the auspices of the National Clinical Effectiveness Committee (NCEC). The NCEC was established by the Department of Health to support evidence-based practice.¹⁰

Box 1 summarises risk groups for whom screening is recommended by the new guidelines. The strength of recommendation reflects the confidence that the desirable effects of screening outweigh the potential undesirable effects. Where the evidence of the risk of HCV infection is clear and/ or the benefit of offering screening is considered high, a strong recommendation to offer screening has been made. When the evidence on the risk of HCV infection and/or potential benefit of screening is less clear, a weak or conditional recommendation has been made, which means that screening should be considered in these groups.

For many risk groups screening is already offered through dedicated health services (eg. addiction services, maternity services, occupational health services), as well as in general practice. For other risk groups the main, or in some cases only, healthcare contact, and therefore opportunity to be offered screening, will be their GP. 

The recommendations for screening of some of the risk groups most likely to be encountered in general practice are discussed further here. The full suite of recommendations, along with the supporting evidence and rationale behind the recommendation, can be viewed in the National Clinical Guideline, or the summary version, which is available at health.gov.ie⁹

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People who use unprescribed or illicit drugs

People who inject drugs (PWID) are a well recognised risk group for HCV infection globally. It is recommended that:

• All those who have ever injected unprescribed or illicit drugs should be offered screening for HCV. This includes those who only injected once, and those who injected any type of drug which was not prescribed, including performance enhancing drugs like steroids, and novel psychoactive substances. 
• Those who initially test HCV negative but who remain at risk of HCV infection should be offered repeat testing on an annual basis, or six monthly if deemed clinically appropriate (strong recommendation).
• There is limited and inconsistent evidence on the risk of HCV from non-injecting drug use (NIDU). NIDU which results in exposure to the blood of another person is a biologically plausible transmission route. Therefore:
• Screening should be offered to all those who have used unprescribed or illicit drugs by a route other than injecting, if there is a possibility of transmission of HCV by the route of administration. This includes those who currently use intranasal drugs (ie. snort or sniff), or have done so in the past, or share other equipment or drugs where there is a risk of contamination with the blood of others, eg. smoking crack pipes (strong recommendation).

People who are homeless

A number of studies in Ireland have shown an association between some homeless populations such as rough sleepers, injecting drug use (IDU) and HCV infection.¹¹ Other risk groups such as migrants may also be disproportionately represented in the homeless population, and in addition rough sleepers may have been exposed to discarded needles. Therefore:

• Homeless people who have a history of engaging in risk behaviours associated with HCV transmission, or who have had a potential HCV risk exposure, should be offered screening (strong recommendation).

Migrants

It has been estimated that adult migrants account for approximately 20% of the total burden of chronic HCV in Ireland, with up to 8,500 migrants with chronic HCV in Ireland.¹² It is recommended that:

• Migrants from a country with an intermediate to high prevalence of HCV (anti-HCV ≥ 2%) should be offered one-off HCV screening (strong recommendation).

A list of such countries is available in Appendix 2 of the guideline.

Heterosexuals potentially exposed sexually

Among heterosexuals in a monogamous relationship, the risk of sexual transmission of HCV is strongly linked to HIV co-infection and there is low or no risk of sexual transmission of HCV among HIV-negative couples. Outside of this context, there is limited evidence on what, if any, sexual behaviours present an increased risk of sexual transmission. There is very limited evidence that sexual partners of people who inject drugs (PWID) and commercial sex workers may be at increased risk of HCV infection. However, this may in fact be due to other non-sexual transmission routes of exposure. Therefore:

• In general, HCV screening of sexual partners of known HCV cases is not recommended in heterosexual couples who are both HIV negative.
• Sexual partners of known HCV cases should be considered for screening in the following situations:

             – If the HCV infected case is a PWID

             – If the case or contact is also HIV positive

• Sexual contacts of PWID, but whose HCV status is unknown or where there is evidence of resolved infection, should be considered for screening (conditional/weak recommendation).

Among heterosexuals attending for sexual health screening:

• HCV testing should be considered part of routine sexual health screening in the following circumstances:

            – People who are HIV positive

            – Commercial sex workers

            – PWID

            – If indicated by the clinical history, eg. unexplained jaundice

            – When other risk factors for HCV as outlined in this guideline are present (conditional/weak recommendation)

Men who have sex with men (MSM)

• HIV-positive MSM should be screened at least annually for HCV 
• HIV-negative MSM should be offered testing annually for HCV as part of an overall STI screen (strong recommendation).

People with tattoos 

Globally, an association between tattooing and HCV infection has been established. The factors associated with increased risk are not clear. Outside of prisons, the association between HCV and tattooing in Ireland is not known. However, the risk is likely to be similar to other countries. Nowadays many commercial tattooing premises in Ireland are likely to employ appropriate infection prevention and control practices. However, there is no regulation of the industry in Ireland to assure standards. For this reason it is recommended that:

• Screening for HCV should be considered for all those with a tattoo. Those most at risk of having acquired HCV through tattooing are those who received tattoos a number of decades ago, in non-professional settings, in prison, in high prevalence countries, or in other circumstances where infection control was poor (conditional/weak recommendation).

Household contacts of a person with HCV infection

Some studies have identified a risk of transmission to household contacts (ie. horizontal transmission) of those infected with HCV, while other studies have shown no increased risk. In evaluating the risk of transmission within a household it is difficult to separate the contribution of other common risk factors (eg. in endemic countries – healthcare exposure). As the risk of transmission is likely to be very low within normal household settings, the promotion of screening of household contacts may lead to an undue level of concern and further stigmatisation of people with HCV. Therefore:

• In general, HCV screening of household contacts (with no sexual or vertical exposure to the HCV positive household member) is not necessary due to the low risk of horizontal household transmission (conditional/weak recommendation).

However, if there are circumstances where household transmission is more likely to have occurred, such as HIV co-infection or injecting drug use in the household, then screening may be considered.

Implementation of the National Clinical Guideline

A plan for putting into action the new screening guidelines for HCV has been developed which builds on the work that is being undertaken by a range of HSE services, non-governmental organisations, health and social care professionals, peer workers and volunteers who already offer HCV testing. 

However, many people in risk groups for HCV infection may not access other healthcare or social services, and general practice is therefore an important setting for reaching people who are vulnerable or marginalised and for reaching groups who may not be aware of their risk of HCV infection. It is also known that when testing for HCV is offered in the community this improves the uptake of screening. ¹³ General practice is therefore an important setting in which to focus efforts to screen for HCV.

Given the availability of drugs that can effectively cure HCV infection, a renewed effort is required to identify the 60% of undiagnosed people in Ireland and link them to care and treatment, and by doing so to reach the goal of elimination of HCV infection by 2030. 

References

1. World Health Organization. Guidelines for screening, care and treatment care of persons with hepatitis C infection. Updated version, April 2016. Geneva: WHO; 2016. Available from: http://apps.who.int/iris/bitstream/10665/205035/1/9789241549615_eng.pdf?ua=1
2. Thornton L, Murphy N, Jones L, Connell J, Dooley S, Gavin S, et al. Determination of the burden of hepatitis C virus infection in Ireland. Epidemiol Infect. 2012;140(8):1461-8
3. Garvey P, O’Grady B, Franzoni G, Bolger M, Irwin Crosby K, Connell J, et al. Hepatitis C virus seroprevalence and prevalence of chronic infection in the adult population in Ireland: a study of residual sera, April 2014 to February 2016. Euro Surveill. 2017;22(30):pii=30579
4. Razavi H, Robbins S, Zeuzem S, Negro F, Buti M, Duberg A-S, et al. Hepatitis C virus prevalence and level of intervention required to achieve the WHO targets for elimination in the European Union by 2030: a modelling study. Lancet Gastroenterol Hepatol. 2017;2(5):325-36
5. EASL Recommendations on Treatment of Hepatitis C 2016. J Hepatol. 2017;66(1):153-94
6. Health Service Executive. National Hepatitis C Treatment Programme [Internet]. Dublin: HSE; 2016 [cited 2017 Nov 1]. Available from: http://www.hse.ie/eng/about/Who/primarycare/hepcpr ogramme%20.html
7. World Health Organization. Global health sector strategy on viral hepatitis 2016-2021; towards ending viral hepatitis. Geneva: WHO; 2016. Available from: http://www.who.int/hepatitis/strategy2016-2021/ghss-hep/en/
8. Health Service Executive. National Hepatitis C Strategy 2011-2014. Dublin: HSE; 2012. Available from: https://www.hse.ie/eng/services/Publications/HealthProtection/HepCstrategy.pdf
9. Department of Health. Hepatitis C Screening (NCEC National Clinical Guideline No. 15 Summary). Dublin: DoH; 2017. Available from: http://health.gov.ie/national-patient-safety-office/ncec/national-clinical-guidelines/prevention/
10. Department of Health. National Patient Safety Office; Clinical effectiveness; Governance; NCEC [Internet]. Dublin: DoH [cited 2017 September 15]. Available from: http://health.gov.ie/national-patient-safety-office/ncec/governance-ncec/
11. O’Reilly F, Barror S, Hannigan A, Scriver S, Ruane L, MacFarlane A, et al. Homelessness: an unhealthy state. Health status, risk behaviours and service utilisation among homeless people in two Irish cities. Dublin: The Partnership for Health Equity; 2015. Available from: http://www.drugsandalcohol.ie/24541/1/Homelessness.pdf
12. European Centre for Disease Prevention and Control. Epidemiological assessment of hepatitis B and C among migrants in the EU/EEA. Stockholm: ECDC; 2016. Available from: http://ecdc.europa.eu/en/publications/Publications/epidemiological-assessment-hepatitis-B-and-C-among-migrants-EU-EEA.pdf
13. Jones L, Bates G, McCoy E, Beynon C, McVeigh J, Bellis MA. Effectiveness of interventions to increase hepatitis C testing uptake among high-risk groups: a systematic review. Eur J Public Health. 2014;24(5):781-8