On this page

1. 1. Summary
2. 2. The disease
3. 3. Routine prevention activities
4. 4. Surveillance objectives
5. 5. Data management
6. 6. Communications
7. 7. Case definition
8. 8. Laboratory testing
9. 9. Case management
10. 10. Environmental management
11. 11. Contact management
12. 12. Special situations
13. 13. References and additional sources of information
14. 14. Appendices

1. Summary

Public health priority

Routine

2. The disease

Infectious agents

The hepatitis C virus (HCV) is a positive strand RNA virus and a member of the flavivirus family of ribonucleic acid (RNA) viruses. At least six HCV genotypes and a large number of subtypes have been described. Each genotype contains numerous subtypes, labelled a, b, or c. Genotypes 1 and 3 are the most common genotypes in Australia ^[1]. The virus mutates frequently so that many variants may coexist in a single patient ^[2].

Reservoir

Humans are the only known natural host. People with chronic infection, as defined by persistent serum HCV RNA, are the major reservoir of infection.

Mode of transmission

HCV is transmitted primarily through blood-to-blood contact, predominantly through the following modes of infection:

• Injecting drug use: The highest risk is related to reuse of needle/syringes, with associated blood contamination, but sharing of other contaminated injecting equipment (swabs, filters, water, spoons, and tourniquets) can lead to transmission.
• Receipt of donated blood, blood products, and organs: Donor screening was introduced in early 1990 in Australia, with current nucleic acid testing virtually eliminating the risk of transmission through blood products in Australia. Blood transfusion may still represent a risk for HCV transmission in countries with limited resources.
• Iatrogenic exposure in health care settings: HCV transmission has occurred in a small number of cases in Australia through blood exposures to health care workers and patients, generally as a result of inadequate infection control practice. Such exposures are likely to occur more frequently in resource-limited countries, particularly those with high HCV prevalence.
• Other procedures involving skin penetration: Tattooing and body piercing may be associated with a small number of cases in Australia, particularly in circumstances where there is poor infection control, e.g. in prisons.

+Other routes of exposure are also associated with HCV transmission:

• Perinatal exposure: The risk of HCV transmission from a mother who has chronic HCV infection to a newborn or infant is from 4 to 7%, with a four to five-fold higher risk if HIV infection is also present in the mother ^[3].
• Sexual exposure: HCV transmission is more common in people with HIV infection, particularly in men who have sex with men (MSM) ^[4,5]. People with HIV who are heterosexual partners of those with HCV are also more likely to acquire HCV ^[6,7]. Transmission to people without HIV through heterosexual unprotected sex has been reported but the risk is extremely low, even in the context of long-term regular partnerships.
• Other potential sources of HCV exposure, including sharing of household equipment (razors, toothbrushes) with potential exposure to blood, are considered to be extremely uncommon modes of HCV transmission.

Incubation period

HCV RNA is detectable within 2 weeks following exposure/infection ^[8] with anti-HCV antibody detectable from 20 to 150 days ^[9]. The majority of people with newly acquired HCV infection are asymptomatic or mildly symptomatic. When present, acute HCV symptoms and peak elevations in liver enzymes occur at around 6 weeks following infection ^[10]. As noted below, most people will progress to chronic infection, and a minority will spontaneously clear infection.

Infectious period

People infected with HCV become infectious very early in the course of infection and certainly from the time that RNA is detectable in the blood. Those who clear infection spontaneously are no longer infectious, but are not immunologically protected, so may be re-infected through subsequent HCV exposure. Those who progress to chronic HCV infection remain infectious unless they successfully clear the infection through treatment. Infectiousness is thought to be influenced by HCV RNA level (viral load), but the viral load range is relatively narrow among people with chronic HCV infection (5 to 7 logIU/mL) ^[9]. There is limited variation in the viral load of an individual case over time.

Clinical presentation and outcome

The majority of people with newly acquired HCV infection are asymptomatic or mildly symptomatic (lethargy, abdominal discomfort). From 15 to 45% of people undergo spontaneous viral clearance (generally within 6 to 12 months of infection) as defined by loss of detectable HCV RNA in the absence of treatment ^[11]. Only a minority of cases will have an acute HCV illness with jaundice and elevated alanine aminotransferase (ALT) ^[9]. Fulminant acute hepatitis C is rare.

Approximately 55 to 85% of those with acute infection will develop chronic HCV infection ^[7] with persistent viraemia and HCV-related liver disease ^[8]. Liver disease progression, through stages of inflammation, fibrosis (mild, moderate, severe) and cirrhosis, occurs in a proportion of those with chronic infection but is not inevitable and is generally slow with a highly variable course. An estimated one-third of those who become chronically infected will develop liver cirrhosis or hepatocellular carcinoma in the long term ^[7,12].

Factors that have been associated in observational studies with higher rates of disease progression include older age at infection, heavy alcohol intake ^[13], regular marijuana smoking, HIV or chronic HBV co-infection, obesity and diabetes ^[14-16]. Among people with HCV-related cirrhosis, the risk of hepatocellular carcinoma is 2-3% per annum ^[7] with a similar risk of progression to liver failure.

In addition to liver disease, HCV has been associated with several extra-hepatic manifestations or syndromes, including autoimmune disorders, mild cognitive impairment and chronic fatigue.

Successful HCV treatment, defined by viral eradication, alters the natural history of the infection. Liver disease regression is generally seen, with reductions in the extent of fibrosis or cirrhosis, even if advanced disease is present pre-treatment. Viral eradication also improves quality of life, including improvements in lethargy and other nonspecific symptoms and cognitive impairment.

Persons at increased risk of disease

Population groups at increased risk are:

• people who inject drugs (PWID)
• those in custodial settings (currently or in the past), because of the high prevalence of both HCV and use of non-sterile injecting, tattooing and piercing equipment in prison populations ^[17,18]
• people from regions of the world with high HCV prevalence, in particular Egypt, Pakistan, Central Asia and Eastern Europe ^[19]. Cases of HCV in people from these regions may be diagnosed late and be associated with liver disease at the time of diagnosis
• people who have been medically treated with blood or blood products in Australia or other high-income countries prior to 1990, or in low and middle-income countries at any time
• Aboriginal and Torres Strait Islander people
• people with HBV or HIV infection, which share HCV risk factors.

Disease occurrence and public health significance

3. Routine prevention activities

Vaccination

There is no vaccine.

Risk mitigation

The risk of transmission of HCV can be reduced by:

• promotion of safe injecting drug use practices, which in turn require the provision of equipment and education
• screening of donated blood and tissues
• maintenance of infection control standards in health care settings and all skin penetration procedures
• promotion of safe sex practices
• education of people with chronic HCV infection and relevant caregivers about the nature of the infection and the means of minimising transmission (see section ’Education’ below)
• making testing available to those at risk
• Tteatment that, in the majority of cases, is curative and therefore eliminates the risk of onward transmission ^[20]

4. Surveillance objectives

Surveillance of HCV aims to collect data to monitor epidemiological trends in HCV, with particular regard to time, place, population groups and risk factors. These data are used to identify and characterise clusters of cases; inform and evaluate policies, interventions and services to reduce the transmission and consequences of HCV infections; and contribute to reporting on the progress of national strategies.

5. Data management

Newly acquired cases should be entered onto the jurisdictional notifiable diseases database within 5 working days of notification (after evidence is obtained for a case being categorized as either newly acquired or unspecified). Core data and (for newly acquired cases) enhanced data sought from clinicians and laboratories should be entered as soon as information becomes available. Data from jurisdictions are collated in the National Notifiable Diseases Surveillance System (NNDSS) and further analysed by the Kirby Institute. Enhanced surveillance information for newly acquired HCV is collected from states and territories but not included in the core national dataset. Unspecified cases also need to be entered and reported to the NNDSS ^[a]. These data are defined in the national core and enhanced HCV datasets (NNDSS Dataset – Enhanced Hepatitis C (Newly Acquired) Surveillance Dataset Field Specifications). Appendix 3 has a sample case report form/data collection based on these specifications for use by PHUs.

^[a] In practice, the majority of newly acquired cases will be entered as unspecified cases and then revised to the newly acquired category after information is collected that satisfies the case definition.

6. Communications

Laboratories performing HCV testing must notify the relevant state and territory health authorities of any new HCV-positive laboratory diagnosis in accordance with the relevant legislation/regulations. In some states and territories, medical practitioners and/or hospital CEOs must also notify the relevant State and Territory health authorities. On receipt of a notification, a state or territory PHU will contact the diagnosing clinician to obtain additional information to determine the appropriate category for the notification and the need for further case investigation.

7. Case definition

HCV surveillance notifications are classified as either ‘newly acquired’ (infection acquired within 24 months prior to diagnosis) or ‘unspecified’ (infection acquired more than 24 months prior to diagnosis or duration not known).

Hepatitis C - newly acquired

Only confirmed cases should be notified.

A confirmed case requires:

• Laboratory definitive evidence, or
• Laboratory suggestive evidence and clinical evidence.

Laboratory definitive evidence

• Detection of anti-hepatitis C antibody from a person who has had a negative anti-HCV antibody test recorded within the past 24 months, or
• Detection of hepatitis C virus by nucleic acid testing from a person who has had a negative anti-HCV antibody test result within the past 24 months, or
• Detection of anti-HCV antibodies in a child aged 18 to 24 months, or
• Detection of hepatitis C virus by nucleic acid testing, in a child aged 3 to 24 months.

Laboratory suggestive evidence

Detection of anti-hepatitis C antibody or hepatitis C virus by nucleic acid testing in a patient with no prior evidence of hepatitis C infection.

Clinical evidence

Clinical hepatitis within the past 24 months (where other causes of acute hepatitis have been excluded) defined as:

• Jaundice, or
• Bilirubin in urine, or
• Alanine transaminase (ALT) is ten times the upper normal limit.

Hepatitis C - Unspecified

Only confirmed cases should be notified.

A confirmed case requires laboratory definitive evidence and the case does not meet any of the criteria for a newly acquired case and is aged more than 24 months.

Laboratory definitive evidence

In a person with no prior evidence of hepatitis C Infection:

• Detection of anti-hepatitis C antibody, or
• Detection of hepatitis C virus by a nucleic acid testing.
  

Clinical evidence

Not applicable.

8. Laboratory testing

Testing guidelines

Two classes of assays are used in the diagnosis of HCV infection: serologic assays that detect specific antibody to HCV (anti-HCV), or HCV antigen; and molecular assays that detect viral nucleic acid.

Serology

Current tests are both sensitive and specific (the specificity of current immunoassays for anti-HCV is greater than 99%). However, false positive results may occur. A positive result is more likely to be a false positive when testing is performed among populations where the prevalence of HCV is low and/or where the reactivity of the assay is low. Therefore, a second immunoassay using an assay with a different antigen source or an immunoblot is routinely performed to confirm new positives. False negative results may occur with severe immunosuppression such as infection with HIV, solid organ transplant recipients, hypo- or agammaglobulinaemia or in patients on haemodialysis ^[21].

Anti-HCV IgG can be detected in the serum or plasma using a number of immunoassays. However, detection of specific antibody does not differentiate between acute and chronic infection, previous exposure, or passive antibody transfer. IgM tests, which usually indicate acute infection, are not clinically useful for HCV. Cases with spontaneous viral clearance will usually remain HCV antibody positive for life.

Nucleic acid testing

A nucleic acid test (e.g. PCR test) detects HCV RNA and is therefore a marker of viraemia and current infectivity. A single negative PCR does not rule out infection, as viraemia may be intermittent, particularly during acute infection. Currently available assays have excellent specificity (from 98 to 99%) ^[21]. Both qualitative and quantitative HCV PCR tests are available but only the former are registered as diagnostic tests. Quantitative HCV PCR tests are only registered for patient management.

Genotyping assays

Determining the specific HCV genotype can be useful in epidemiological studies and in clinical management because it is associated with treatment outcome ^[21].

Test interpretation

The diagnosis of acute, chronic or cleared HCV infection requires testing of serum for both antibody to HCV (anti-HCV) and for HCV RNA. The differentiation of acute from chronic HCV infection may be difficult or impossible in the short-term and require individual assessment of clinical information, including history of symptoms and risk factors and previous test results, including any previous liver function tests.

After exposure, HCV RNA is usually detectable in serum before antibody; HCV RNA can be identified within two weeks following exposure ^[8] whereas anti-HCV is detectable between 20 to 150 days following exposure ^[9].

Table 1. Interpretation of test results

Anti-HCV	HCV RNA	Interpretation	Clinical action
Positive	Positive	Acute or chronic HCV, depending on the clinical context*	Treatment is recommended for all HCV cases with a positive HCV RNA. Treating clinicians should consider treatment and/or referral to specialist services.
Positive	Negative	Cleared HCV infection or false positive serology result[b]	Retest in 2-3 weeks, only if ALT is raised
Negative	Positive	Early acute HCV infection* or chronic HCV with immunosuppression or false positive HCV RNA test	Retest in 2-3 weeks; Refer for specialist case management
Negative	Negative	Absence of HCV infection	Provide information and retest. Retest if exposure was known to be recent

*A newly acquired infection is defined as a positive anti-HCV test together with evidence of a negative HCV antibody test result within the past two years; or a positive HCV PCR and negative antibody test, followed by a positive result on both tests within at most two years.

^[b]After recent exposure viral loads can oscillate widely, and can fall below the limit of detection.

Detection of anti-HCV in a person with a negative test for HCV RNA usually represents past, cleared HCV infection. Rarely this result can indicate acute HCV infection during a period of transient clearance of HCV RNA, or a false positive or false negative result on the antibody and RNA results respectively. Re-testing for HCV RNA is recommended to confirm the resolution of HCV infection.

A negative anti-HCV test with a HCV RNA detection may represent:

• the early stage of acute infection prior to the development of antibody, or
• chronic infection in an immunosuppressed individual, or
• a false positive HCV RNA result.

Again, re-testing for anti-HCV and HCV RNA is recommended ^[21].

9. Case management

Response times

Public health action should commence within 3 working days of notification of a newly acquired confirmed case. Unspecified cases should be provided with information (refer Appendix 2 Sample HCV information sheet) and followed up at the discretion of the PHU director.

Response procedure

Determining the source of infection for newly acquired cases may permit identification of other cases and interrupt infection transmission. Information regarding exposures during the period six weeks to six months before the onset of the illness should be sought. A PHU investigation checklist is provided in Appendix 1.

Case investigation

The response to a notification (newly acquired cases only) will normally be carried out in collaboration with the case's health care providers. Regardless of who does the follow-up, PHU staff should ensure that action has been taken to determine whether the case has any history of injecting illicit drugs in a time period relevant to the acquisition of HCV. If so, the case should be provided with information about the disease (refer Appendix 2 Sample HCV information sheet). If not, information should still be provided about the disease and an exposure investigation carried out.

Exposure investigation

For newly acquired cases not associated with injecting illicit drugs, the possible time period of acquisition should be defined. Information should then be sought regarding potential exposures during the period six months before the start of this period with the purpose of 1) ascertaining the source of the infection and 2) determining whether there might have been others exposed to the same source.

This should include information about history of:

• receipt of blood or blood products
• dental or surgical procedures, renal dialysis or other medical procedures
• tattooing, ear or body piercing, or acupuncture
• needle stick or similar injury
• accidental exposure of skin, eyes, mucous membranes, or a wound to blood of another person
• work in occupational settings with potential for blood exposure.

Further investigation of any identified potential exposures depends on their nature, and other factors including whether or not any other HCV cases have been reported that share an association with the same potential exposure. Inform the jurisdictional health authority.

If 2 or more cases are determined to be linked with the same putative source of exposure, then a search for additional cases is strongly indicated as part of the investigation (see Contact Management below).

Case treatment

Cases should be tested for other blood borne virus (HBV and HIV) infections and vaccinated against HBV if non-immune.

Discussing, offering and providing treatment are the responsibility of the case’s clinician. Curative therapies have been available for a number of years and can now cure more than 90% of HCV infections, even covering genotypes that were once poorly responsive to treatment ^[7].

The viral suppression and eradication achieved with treatment is important for the individual patient because it prevents disease progression, and for public health control because it eliminates the risk of viral transmission from that person. Reinfection following treatment can nevertheless occur in association with ongoing injecting illicit drug use ^[22] and sexual transmission in HIV infected MSM.

Education

The case (or care-provider as appropriate) should be informed of measures needed to prevent onward transmission while the case is infectious. Standard precautions include:

• not sharing items that have the potential to transfer blood (for example razors and toothbrushes, injecting equipment)
• covering any open wound with an impermeable dressing
• undertaking safe sex practices if HIV co-infection is present
• not donating blood.

A fact sheet on HCV infection should be made available to the case and family and other potentially exposed individuals to provide information about the nature of the infection and the mode of transmission (refer Appendix 2 Sample HCV information sheet).

Isolation and restriction

The risk of transmission of HCV through personal contact not involving blood is very low (except sexual contact if HIV co-infection is present). Hence, no specific precautions are required other than standard infection control measures.

There may be work restrictions if a case occurs in some occupational groups (see ‘special cases’ and jurisdictional specific requirements in appendices). Isolation and restrictions are otherwise generally not required.

10. Environmental management

None required, except when a cluster of cases is reported.

11. Contact management

Contacts include all people who have had exposure to blood from a person with current HCV infection, including through the use of the same injecting equipment as the case subsequent to the date when infection was acquired in the case. Also included is a child born to a woman with HCV whose infection could have occurred prior to the birth of the child. Contacts may also include sexual partners with HIV infection. Other sexual partners may be considered if they are long-term.

For infections acquired through a procedure involving skin penetration in a medical or other setting, contacts are those who received the same procedure in the same setting, within the time period that the risk was considered, on the best available evidence, to be present.

Household contacts of a person with HCV are not at risk of person-to-person transmission. For cases where there is evidence that HCV acquisition occurred through medical or other skin penetration procedures (generally considered to be a very small minority of cases in the Australian setting), the public health response should include identification and notification of others who may have been exposed in the same setting and should be done in conjunction with the jurisdictional health authority.

Notification of those potentially exposed to HCV infection will alert them to the risk, and thereby enable counselling, testing, medical management as required and education regarding behavioural risk modification if indicated. The responsibilities for contact tracing and management vary between jurisdictions, and may include clinicians, sexual health centres and/or PHUs or Departments of Health. There are some situations in which it is important that relevant jurisdictional health authorities are informed (see Section 12 – Special Situations) even if contact tracing is managed at a local level. For cases acquired through a skin penetration procedure, contact tracing can serve the additional purposes of further investigating or determining the degree of contact with the source, and identifying and ultimately eliminating the risk of further exposure to the identified source of HCV - refer (Australian Contact Tracing Manual).

The extent of contact tracing will depend on an assessment of both the duration and likely source of infection. If the case is determined to be newly acquired and there is a history of injecting drug use in the relevant time period, the notifying doctor may discuss contact tracing of drug-use partners with the case; PHU support may be made available if requested by the doctor. The Australian Contact Tracing Manual provides guidance.

If the case is newly acquired and the source of infection has been determined (or assessed as likely) to be a medical or other skin penetration procedure, trace back using medical or other records to identify others potentially exposed in the same setting up to 6 months prior to onset of acute symptoms in the index case. Depending on the nature of the source, this process can be complex and involve significant logistical and resource challenges and should occur in conjunction with the jurisdictional health authority. It may require a public announcement to alert potentially exposed people if appropriate records are not available. It may also require resources additional to those available routinely. For cases with an unspecified duration of infection, or those for which the procedure took place many years ago, trace back of this kind may not be feasible.

Prophylaxis

Nil.

Education

Nil.

Isolation and restriction

Nil.

12. Special situations

Cases among health care workers

If the case occurs is a health care worker who performs exposure prone procedures, it should be assessed and monitored in accordance with Australian National Guidelines for the Healthcare workers who live with blood borne viruses, perform exposure prone procedures, or are at risk of exposure to blood borne viruses.

Suspected health care/iatrogenic acquired infection

If more than one case occurs among patients of the same health care provider or facility, or tattooist or other skin penetration service provider, or in other circumstances which might suggest the possibility of iatrogenic infection, initiate an investigation and notify the relevant state/territory communicable diseases branch immediately.

Blood transfusion and transplantation

The Australian Red Cross Blood Service and relevant jurisdictional office should be notified immediately if a person with acute or chronic HCV infection has donated blood or plasma, or if transfused blood or blood products are suspected as the possible source of infection in a newly diagnosed case of HCV.

Cluster of cases

Additional actions may be required where a cluster of cases in place or time is detected through analysis of case exposure history. The goal of these actions would be is to identify the source of infection and potential risk factors, thereby informing public health action.

Infants who are anti-HCV antibody positive

Children under 18 months of age who test positive for anti-HCV antibody should be followed up with either:

• testing for HCV by a nucleic acid test at or after 3 months of age; or
• repeat anti-HCV antibody at 18 months of age

to determine whether or not the child is a confirmed newly acquired case.

13. References and additional sources of information

1. Sievert W, Altraif I, Razavi HA, Abdo A, Ahmed EA, Alomair A, et al. A systematic review of hepatitis C virus epidemiology in Asia, Australia and Egypt. Liver international : official journal of the International Association for the Study of the Liver. 2011;31 Suppl 2:61-80. Epub 2011/06/18.
2. Kelly D, Skidmore S. Hepatitis C-Z: recent advances. Archives of disease in childhood. 2002;86(5):339-43. Epub 2002/04/24.
3. Roberts EA, Yeung L. Maternal-infant transmission of hepatitis C virus infection. Hepatology. 2002;36(5 Suppl 1):S106-13. Epub 2002/10/31.
4. Fierer DS, Uriel AJ, Carriero DC, Klepper A, Dieterich DT, Mullen MP, et al. Liver fibrosis during an outbreak of acute hepatitis C virus infection in HIV-infected men: a prospective cohort study. The Journal of infectious diseases. 2008;198(5):683-6. Epub 2008/07/17.
5. van de Laar T, Pybus O, Bruisten S, Brown D, Nelson M, Bhagani S, et al. Evidence of a large, international network of HCV transmission in HIV-positive men who have sex with men. Gastroenterology. 2009;136(5):1609-17. Epub 2009/05/08.
6. Terrault NA. Sexual activity as a risk factor for hepatitis C. Hepatology. 2002;36(5 Suppl 1):S99-105. Epub 2002/10/31.
7. WHO. Guidelines for the Screening,Care and Treatment of Persons with Hepatitis C Infection. France: World Health Organization; 2014; Available from: www.who.int.
8. Blackard JT, Shata MT, Shire NJ, Sherman KE. Acute hepatitis C virus infection: a chronic problem. Hepatology. 2008;47(1):321-31. Epub 2007/12/29.
9. Busch MP, Shafer KA. Acute-phase hepatitis C virus infection: implications for research, diagnosis, and treatment. Clinical infectious diseases : an official publication of the Infectious Diseases Society of America. 2005;40(7):959-61. Epub 2005/04/13.
10. Mosley JW, Operskalski EA, Tobler LH, Andrews WW, Phelps B, Dockter J, et al. Viral and host factors in early hepatitis C virus infection. Hepatology. 2005;42(1):86-92. Epub 2005/06/15.
11. Jauncey M, Micallef JM, Gilmour S, Amin J, White PA, Rawlinson W, et al. Clearance of hepatitis C virus after newly acquired infection in injection drug users. The Journal of infectious diseases. 2004;190(7):1270-4. Epub 2004/09/04.
12. Seeff LB. Natural history of chronic hepatitis C. Hepatology. 2002;36(5 Suppl 1):S35-46. Epub 2002/10/31.
13. Freeman AJ, Dore GJ, Law MG, Thorpe M, Von Overbeck J, Lloyd AR, et al. Estimating progression to cirrhosis in chronic hepatitis C virus infection. Hepatology. 2001;34(4 Pt 1):809-16. Epub 2001/10/05.
14. Mallat A, Hezode C, Lotersztajn S. Environmental factors as disease accelerators during chronic hepatitis C. Journal of hepatology. 2008;48(4):657-65.
15. Salmon-Ceron D, Lewden C, Morlat P, Bévilacqua S, Jougla E, Bonnet F, et al. Liver disease as a major cause of death among HIV infected patients: role of hepatitis C and B viruses and alcohol. Journal of hepatology. 2005;42(6):799-805.
16. Chen SL, Morgan TR. The natural history of hepatitis C virus (HCV) infection. International journal of medical sciences. 2006;3(2):47.
17. Gates JA, Post JJ, Kaldor JM, Pan Y, Haber PS, Lloyd AR, et al. Risk factors for hepatitis C infection and perception of antibody status among male prison inmates in the Hepatitis C Incidence and Transmission in Prisons Study cohort, Australia. Journal of urban health : bulletin of the New York Academy of Medicine. 2004;81(3):448-52. Epub 2004/07/27.
18. Hellard ME, Aitken CK, Hocking JS. Tattooing in prisons--not such a pretty picture. American journal of infection control. 2007;35(7):477-80. Epub 2007/09/04.
19. Lavanchy D. Evolving epidemiology of hepatitis C virus. Clinical microbiology and infection : the official publication of the European Society of Clinical Microbiology and Infectious Diseases. 2011;17(2):107-15. Epub 2010/11/26.
20. Rolls DA, Sacks-Davis R, Jenkinson R, McBryde E, Pattison P, Robins G, et al. Hepatitis C transmission and treatment in contact networks of people who inject drugs. PloS one. 2013;8(11):e78286. Epub 2013/11/14.
21. Ghany MG, Nelson DR, Strader DB, Thomas DL, Seeff LB. An update on treatment of genotype 1 chronic hepatitis C virus infection: 2011 practice guideline by the American Association for the Study of Liver Diseases. Hepatology. 2011;54(4):1433-44. Epub 2011/09/08.
22. Grebely J, Prins M, Hellard M, Cox AL, Osburn WO, Lauer G, et al. Hepatitis C virus clearance, reinfection, and persistence, with insights from studies of injecting drug users: towards a vaccine. The Lancet infectious diseases. 2012;12(5):408-14. Epub 2012/05/01.

14. Appendices

• Appendix 1: PHU checklist for newly acquired HCV cases (from the CDNA Hepatitis C SoNG v1.0)