Page content: Victorian statutory requirement | Infectious agent | Identification | Incubation period | Public health significance & occurrence | Reservoir | Mode of transmission | Period of communicability | Susceptibility & resistance | Control measures | Outbreak measures | Additional sources of information

Victorian statutory requirement

Hepatitis C infection (Group B disease) must be notified in writing within five days of diagnosis.

Specific information is required to be notified under the Health (Infectious Diseases) Regulations 2001. In certain circumstances the attending doctor and patient may be asked to complete a questionnaire to collect additional information. All information collected by the Department of Human Services is treated as confidential. It is used for reasons such as detecting disease trends and to inform public health action and policy development.

School exclusion is not required.

Infectious agent

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

Identification

Clinical features
Most infections with HCV are asymptomatic and acute infection may only be detected in patients by the development of elevated serum alanine aminotransferase (ALT) levels. When symptoms and signs do occur, they are similar to other forms of viral hepatitis but usually milder. Estimates vary but between 10% and 50% of people infected with HCV completely recover and are clear of the virus in the subsequent few years. Community based studies report a greater likelihood of viral clearance compared with hospital-based studies. If symptoms of ongoing disease occur they may be non-specific and include fatigue, headaches and nausea.

Method of diagnosis
HCV infection is confirmed by using the combination of a HCV antibody test and PCR to detect HCV RNA. A positive antibody test implies previous infection by the virus and a positive HCV RNA implies ongoing infection.

Antibodies are directed against the products of expressed clones or peptides of the HCV. First generation enzyme immunoassay (EIA) for antibody detection became available in Australia in 1990 and since then second and third generation EIA tests with improved sensitivity and specificity have been developed.

Supplemental tests are also available in the form of recombinant immunoblot assays (RIBA). The significance of equivocal reactivity detected by EIA tests and indeterminate reactivity detected by RIBA testing remains problematic in low risk groups.

A positive HCV RNA test is a marker for viraemia and ongoing infection. A single negative PCR does not exclude infection as viraemia may be intermittent. The patient should be retested in six to 12 months time.

Current EIA tests cannot distinguish between patients who are currently infectious and those who have recovered from infection and developed immunity.

Incubation period

The incubation period ranges from two weeks to six months. It is most commonly six to nine weeks after which serum ALT levels rise. Current HCV antibody tests become positive two to three months after exposure.

Public health significance & occurrence

Hepatitis C occurs worldwide. Current estimates suggest that more than 200 000 Australians have been infected with this virus and that 11 000 new infections are occurring each year. Specific groups such as injecting drug users are at greater risk of HCV infection.

Three quarters of people infected with HCV become chronic carriers of the virus. Of those chronically infected, approximately 10–20% will develop liver cirrhosis over a period of 15–40 years and an estimated 5% will develop hepatocellular carcinoma after 40 years of infection.

There are at least six major genotypes of HCV. At present the main genotypes found in the Australian population are 1 (54%), 3 (36%) and 2 (6%).

Reservoir

Humans.

Mode of transmission

Hepatitis C is primarily transmitted by blood-to-blood contact.

In Australia and other Western countries the sharing of injecting equipment by intravenous drug users is the most common mode of transmission. Tattooing, ear piercing and body piercing using unsterile equipment are other potential sources. There is a high prevalence of HCV in people who have been in prison because of the high likelihood of injecting drug use and tattooing.

Health care and laboratory staff who handle blood and blood products are at increased risk. The Centers for Disease Control and Prevention report that the risk of contracting hepatitis C after percutaneous exposure such as needle stick or sharps injury from the blood of a person with hepatitis C antibody has been estimated at 0–7% (average 1.8%). The risk of transmission is negligible if the source is HCV RNA-negative.

Sexual transmission rates of HCV infection are very low. 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.

Mother to baby transmission is approximately 5–6% and is thought to occur only when the mother is HCV RNA positive. The likelihood of transmission is increased if the mother is also infected with HIV. Although HCV has occasionally been detected in breast milk there is no evidence that HCV is transmitted from mother to child by breast feeding.

Community or household transmission of HCV is considered rare.

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 they may be unwilling to discuss the possibility.

Re-use of poorly cleaned needles by medical practitioners and others in some countries and cultural practices that involve skin piercing are other potential sources of infection.

Period of communicability

Communicability occurs during the acute clinical stage of HCV infection and indefinitely in the chronic carrier stage. All HCV positive individuals should be considered potentially infectious although the risk is minimal in the non-viraemic (PCR negative) individual.

Susceptibility & resistance

All non immune 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 re-infected 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

Preventive measures
All health care 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 depends mainly on the genotype and sometimes whether previous treatment has failed. Combined therapy with alpha interferon and ribavirin or pegylated interferon and ribavirin are possible treatment regimens.

Counselling of the patient is a very important part of the 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
• share injecting equipment
• share personal items such as toothbrushes or razors.

They should also be advised to:

• consider discussing their condition with their health care provider when undergoing any dental or medical procedure
• wipe up any blood spills with single use disposable paper towels and clean area with detergent and warm water
• cover any cuts or wounds with an occlusive waterproof dressing
• place blood-stained 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 health care provider. Safe sex is not routinely recommended among long term monogamous couples.

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

Prophylactic immunoglobulin for contacts has no role.

Control of environment
Not applicable.

Outbreak measures

Special settings
Health care workers
Registration boards should be consulted in relation to their policies regarding health care workers with blood-borne viruses. For example, the Medical Practitioners Board of Victoria has a policy on medical practitioners and medical students who carry a blood-borne virus which is available at the Medical Practitioners Board of Victoria website. Recommendations are also included in Infection control guidelines for the prevention of transmission of infectious diseases in the health care setting which is available at the Australian Government Department of Health and Ageing website.

Antenatal care
Antenatal care should include a comprehensive assessment of hepatitis C risk factors. Women found to be at higher risk of hepatitis C 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 Infection control guidelines for the prevention of transmission of infectious diseases in the health care at the Australian Government Department of Health and Ageing website.

Additional sources of information

• Centers for Disease Control 1997, ‘Notice to readers – Recommendations for follow-up of health-care workers after occupational exposure to hepatitis C’, Morbidity and Mortality Weekly Report, vol. 46, no. 26, pp. 603–606.
• Centers for Disease Control 2001, ‘Updated US public health service guidelines for the management of occupational exposures to HBV, HCV and HIV and recommendations for postexposure prophylaxis, Morbidity and Mortality Weekly, vol. 50, RR –11, pp. 1–42.
• Charles, PG, Angus, PW, Sasadeusz, JJ & Grayson, LM 2003, ‘Management of healthcare workers after occupational exposure to hepatitis C’, Medical Journal of Australia, vol. 179, no. 3, pp. 153–157.
• Crofts, N, Dore, G & Locarnini, S (eds.) 2001, Hepatitis C – An Australian perspective, IP Communications.
• Dore, G, Grulich, A, Kidd, M, Hoy, J McCoy, R, Mijch, A & Strasser, S 2001, HIV/Viral hepatitis – a guide for primary care, Australasian Society for HIV Medicine
  http://www.ashm.org.au
• Mehta, SH, Cox, A, Hoover, DR, Wang, XH, Mao, Q, Ray, S, et al. 2002, ‘Protection against persistence of hepatitis C’, Lancet, vol. 359, no. 9316, pp. 1478–1483.
• Victorian Department of Human Services 2002, Hepatitis C Strategy 2002–2004