Hepatitis C

Notification requirement for hepatitis C

Hepatitis C infection is a ‘routine’ notifiable condition and must be notified by medical practitioners and pathology services in writing within 5 days of diagnosis.

The treating doctor and patient may be asked to complete a confidential questionnaire by the department to collect additional information. This is used for the detection of disease trends and policy development.

This is a Victorian statutory requirement.

Primary school and children’s services centre exclusion for hepatitis C

Exclusion is not required.

Infectious agent of hepatitis C

Hepatitis C virus (HCV) is a small RNA virus that is closely related to the flaviviruses and animal pestiviruses.

Identification of hepatitis C

Clinical features

More than 90 per cent of infections with HCV are asymptomatic, and acute infection may only be detected in patients following the investigation of elevated liver enzymes. When symptoms and signs do occur, they are similar to other forms of viral hepatitis, but usually milder. Symptoms include anorexia, abdominal discomfort, nausea, vomiting, lethargy, and occasionally rashes and arthralgia. Jaundice and dark urine may follow. A high percentage of people (50–80 per cent) develop a chronic infection. However, if infection resolves and the virus is cleared, the person is not immune and can be reinfected. If symptoms of ongoing disease occur, they may be nonspecific and include fatigue, headaches and nausea. Hepatitis C may trigger autoimmune disease such as vasculitis, arthritis or nephritis, sometimes associated with cryoglobulinaemia.

Diagnosis

HCV infection is confirmed by using the combination of an HCV antibody test and polymerase chain reaction (PCR) to detect HCV RNA. A positive antibody test implies previous infection with the virus, and a positive HCV RNA test implies ongoing infection.

Antibodies are directed against the products of expressed clones or peptides of HCV. The enzyme-linked immunosorbent assay (ELISA) for antibody detection is reproducible and inexpensive, and is used for screening at-risk populations. A negative ELISA test suffices to exclude a diagnosis of chronic HCV infection in immunocompetent people. The third-generation ELISA is sensitive and specific enough to obviate the need for a confirmatory recombinant immunoblot assay (RIBA). RIBA is now used as supplementary testing for equivocal results – for example, positive ELISA and negative HCV PCR. It must be noted that these tests do not differentiate between acute, chronic or resolved infections. Antibodies can persist for up to 20 years after resolution of infection in some cases.

Acute or chronic HCV infection, as detected by ELISA, should be confirmed by testing for HCV RNA in serum by PCR. A positive qualitative HCV RNA test is a marker of viraemia and ongoing infection. A single negative PCR does not exclude infection, as viraemia may be intermittent, and the patient should be retested in 6–12 months. A quantitative determination of viral load and HCV genotype will provide information, will aid in guiding treatment dose and duration, and can act as a prognostic indicator of potential response to interferon-based therapy.

Any person positive for HCV should also be tested for hepatitis B virus, human immunodeficiency virus (HIV) and tuberculosis.

Incubation period of hepatitis C virus

The incubation period ranges from 2 weeks to 6 months. It is most commonly 6–9 weeks, after which serum alanine transaminase (ALT) levels rise. Current HCV antibody tests become positive 2–3 months after exposure.

Public health significance and occurrence of hepatitis C

Hepatitis C occurs worldwide. Current estimates suggest that more than 250,000 Australians have been infected with this virus. An estimated 9,700 new cases of HCV occurred in 2005; however, only 354 cases were determined to be newly acquired, as most cases are subclinical, go unnoticed and are incidentally found.

Three-quarters of people infected with HCV become chronically infected with the virus. Of these, approximately 10–20 per cent will develop liver cirrhosis over a period of 15–40 years, and an estimated 5 per cent will develop hepatocellular carcinoma after 40 years of infection. This risk can be exacerbated by liver injury, especially concurrent alcohol use. Five per cent of infants born to HCV-infected women develop HCV infection. Breastfeeding is not an additional risk factor for transmission unless the nipples are cracked, or the baby has cuts on or inside the mouth.

There are at least six major genotypes of HCV. At present, the main genotypes found in the Australian population are 1 (54 per cent), 3 (36 per cent) and 2 (6 per cent). It is important to determine the genotype because this guides therapy.

Reservoir of hepatitis C virus

Humans are the reservoir.

Mode of transmission of hepatitis C virus

Hepatitis C is primarily transmitted by blood-to-blood contact. The risk of transmission is dependent on the mode (e.g. open-bore needle versus suture needle) and status of the source. The average risk is 1.8 per cent (0–7 per cent) via a needlestick or sharps injury from an HCV RNA–positive patient, and negligible if the source is HCV RNA negative.

Routes of transmission include:

• use of nonsterile injecting equipment
• needlestick injury or other parenteral inoculation; this includes blood and blood product transfusions before blood-bank screening
• some household activities, such as sharing razors or toothbrushes (very rare)
• invasive procedures with inadequate infection control (e.g. dental or medical procedures, tattoos or body piercing)
• vertical transmission from mother to neonate, around the time of birth (although there is a low risk of approximately 5 per cent with an HCV RNA–positive mother; breastfeeding has no additional risk).

Rates of sexual transmission of HCV infection are negligible. The risk is increased if the HCV-positive partner is immunocompromised, as the viral blood titre may be increased, or when there is the possibility of blood-to-blood contact – for example, sex during menstruation and traumatic sexual practices.

A proportion of HCV-positive individuals do not fall into any known risk subgroup. They may have forgotten that they had exposure to injecting drugs many years ago or may be unwilling to discuss the possibility.

Period of communicability of hepatitis C

Communicability is from 1 or more weeks before the onset of symptoms, and during the acute clinical stage of HCV infection. All HCV-positive individuals – that is, people with chronic infection – should be considered potentially infectious, although the risk is minimal in the nonviraemic (PCR-negative) individual. Peaks in viral concentration appear to correlate with peaks in ALT activity.

Susceptibility and resistance to hepatitis C

All nonimmune people are susceptible to infection. The degree of immunity following infection is uncertain. If infection resolves and the virus is cleared, the person can be reinfected with the same and other genotypes. However, there is some evidence from cohort studies that the likelihood of reinfection is reduced after the first HCV infection.

Control measures for hepatitis C

Preventive measures

All healthcare providers with potential contact with blood or body fluids should use standard precautions.

Use single-use equipment for all skin-penetration procedures, or use appropriate cleaning, disinfection or sterilisation methods when reusable instruments are used for any procedure. This includes needles.

Control of case

All people diagnosed with HCV infection should be reviewed by a hepatitis specialist (either a gastroenterologist or an infectious diseases physician), and an assessment made of the likelihood of disease progression. Treatment is offered based on the presence of liver fibrosis.

Length of treatment and type of treatment depend mainly on the genotype and sometimes whether previous treatment has failed. Combined therapy with pegylated interferon and ribavirin is a possible treatment regimen. Newer antiviral agents may also be available via clinical trials.

Counselling of the patient is a very important part of management. This counselling should include:

• exploring the likely source of the infection
• current knowledge of the natural history
• possible symptoms
• advice on prevention of further transmission of infection
• lifestyle issues, such as immunisation against hepatitis A and B, minimisation of alcohol intake, cessation of smoking and healthy diet.

The patient should be advised not to:

• donate blood or body organs
• use nonsterile injecting equipment
• share personal items such as toothbrushes or razors.

They should also be advised to:

• consider discussing their condition with their healthcare provider when undergoing any dental or medical procedure
• wipe up any blood spills with single-use disposable paper towels, and clean the area with detergent and warm water
• cover any cuts or wounds with an occlusive waterproof dressing
• place bloodstained paper tissues, sanitary towels or dressings in a plastic bag before disposal
• use safer sex practices. People in long-term stable relationships will need to discuss condom use with their healthcare provider.

Control of contacts

There is no vaccine available for the prevention of hepatitis C.

Post-exposure prophylaxis with immunoglobulin has no role.

Control of environment

Not applicable.

Outbreak measures for hepatitis C

Not applicable.

Special settings

Healthcare workers

Registration boards should be consulted in relation to their policies regarding healthcare workers with bloodborne viruses. Recommendations are also included in Australian guidelines for the prevention and control of infection in healthcare at the National Health and Medical Research Council website.

Antenatal care

Antenatal care should include a comprehensive assessment of hepatitis C risk factors. Women found to be at higher risk of HCV infection or exposure should be encouraged to undergo hepatitis C antibody screening.

Other settings

All workplaces should have policies and procedures in place regarding action to be taken in the event of a blood spill or sharps injury. Further information can be found in Australian guidelines for the prevention and control of infection in healthcare at the National Health and Medical Research Council website.

Further information

Crofts N, Dore G, Locarnini S (eds) 2001, Hepatitis C – an Australian perspective, IP Communications.