Chapter last reviewed and updated in May 2012.
New Zealand Epidemiology
Most cases of hepatitis C (HCV) in New Zealand have a history of injecting drug use or a history of sexual contact with a confirmed HCV case. Body piercing and tattooing are less common exposures.
The National Needle Exchange Blood-borne Virus Seroprevalence Survey (undertaken in 2004) found that the prevalence of HCV infection among injecting drug users was high (70 percent) and was strongly associated with age and duration of injecting.
More detailed epidemiological information is available on the Institute of Environmental Science and Research (ESR) surveillance website.
Hepatitis C infection is often asymptomatic but may present as an illness with variable symptoms of lethargy, anorexia and jaundice.
The current definition for acute hepatitis C includes cases where there has been documented seroconversion within a 12-month period, even in the absence of clinical illness.
Only acute cases of hepatitis C are notifiable.
Laboratory test for diagnosis
Laboratory confirmation requires positive anti-HCV serology or detection of HCV nucleic acid.
- Under investigation: A case that has been notified, but information is not yet available to classify it as probable or confirmed.
- Probable: Not applicable.
- documented seroconversion to HCV when the most recent negative specimen was within the last 12 months, or
- a positive anti-HCV antibody test or nucleic acid test and a clinical illness consistent with acute HCV within the previous 12 months where other causes of acute hepatitis can be excluded.
- Not a case: A case that has been investigated and subsequently found not to meet the case definition.
Spread of infection
2 weeks to 6 months, commonly 6–9 weeks.
Mode of transmission
Almost all transmissions in New Zealand occur through sharing contaminated needles and other equipment during recreational intravenous drug abuse. Occupational sharps injuries, tattooing and body piercing have also been implicated. Sexual and vertical (mother to child) transmissions are uncommon. Percutaneous exposure to contaminated blood and blood products carries a risk of HCV infection. Before routine screening of donors for HCV was introduced in July 1992, people who received a blood transfusion or blood products were also at risk.
Period of communicability
From 1 week before onset of first symptoms. Infection usually persists indefinitely without treatment. Infectivity correlates with serum HCV RNA levels.
Only confirmed cases are notifiable but attending medical practitioners or laboratories should immediately discuss any new cases with their local medical officer of health.
Management of case
Obtain a history of intravenous drug use, sexual contacts, body piercing, tattooing, contact with a known case, blood or blood product transfusions, occupational sharps injuries and overseas travel.
Although newly diagnosed chronic HCV is not notifiable, a referral to a primary health care provider for appropriate clinical care should be offered in all cases.
No precautions other than standard precautions are indicated for anti-HCV-positive cases in health care facilities.
In almost all cases, there are no restrictions on work, attendance at early childhood services or school or other community activities. Follow local protocols for high-risk occupations (for example, dentistry, surgery).
Cases should be counselled to disclose their condition to other health care workers and sexual partners. It may be appropriate for a doctor to inform other health professionals involved in the management of a case of the infectious status of that case when such information is relevant to clinical safety. Adherence to the Privacy Act 2020 and Codes and Medical Council Guidelines is essential.
Advise the case and their caregivers of the nature of the infection and its mode of transmission.
Specific recommendations to prevent spread include:
- not donating blood, organs, semen or tissue
- not sharing drug-injecting equipment
- not sharing razors or toothbrushes
- using safe sex practices and informing sexual partners
- covering cuts and sores with dressings
- informing health care workers (including dentists) of infection.
Management of contacts
All people who have shared drug-injecting equipment, suffered a sharp injury with a contaminated needle or some other significant percutaneous exposure, had long-term sexual exposure to a case during the suspected period of communicability or are newborn children of cases.
Members of the same household are not considered to be contacts unless they have met one or more of the above conditions.
Ongoing primary health clinical care as the lead for appropriate specialist follow-up, including ongoing diagnostic testing and imaging.
Restriction and prophylaxis
The exposed contact should be advised regarding the risk of transmission and the need for follow-up testing by a professional counsellor(s) as part of the primary health care multidisciplinary team approach to ongoing clinical care.
The Ministry of Health contracts the Hepatitis Foundation of NZ to provide a hepatitis B surveillance programme to eligible carriers. This programme provides regular hepatitis serology and liver function testing, enabling timely referral in cases of early evidence of liver disease and/or cancer. The Hepatitis Foundation also provides some services for hepatitis C follow-up and information.
Other control measures
Identification of source
The medical officer of health is responsible for identifying and managing a cluster of cases.
Clean equipment and surfaces potentially contaminated with blood or body fluids.
See ‘Counselling’ above.
Needle and syringe exchange programmes exist in pharmacies and community groups throughout New Zealand. A list of outlets is available from the New Zealand Needle Exchange Programme website.
Ensure complete case information is entered into EpiSurv.
If a cluster of cases occurs, contact the Communicable Diseases Team at the Ministry of Health, and outbreak liaison staff at ESR, and complete the Outbreak Report Form.
 Also sometimes referred to as ‘incident’ cases.
 Ministry of Health correspondence DS 20 07 0, 3 December 1999.