The majority of clinical hepatitis that was previously attributed to hepatitis "Non-A, Non-B" has been shown to be the result of infection with hepatitis C virus (HCV). HCV accounts for 20-40% of acute hepatitis world-wide. In North America it is estimated that approximately 1% of the population is currently infected with HCV. In general (75% of the time), HCV causes subclinical infections, i.e., infection is only recognized by detecting abnormal serum transaminases and/or detecting anti-HCV antibody (a marker of HCV infection and infectivity). HCV is rarely associated with fulminant (rapidly progressive) liver failure. HCV infection is important, however, because most people who are infected with HCV (approximately 60-80%) will develop chronic illness. Of persons who are chronically infected approximately 30% will develop chronic hepatitis which leads to cirrhosis over the next 15-30 years and these individuals will be at increased risk of developing hepatocellular carcinoma (hepatoma).

Studies have shown that there is a higher prevalence of chronic HCV infection in persons who have received blood products prior to the availability of universal anti-HCV antibody testing in 1990. Approximately 20-40% of patients who received large amounts of unscreened blood products e.g., haemophiliacs and patients in dialysis units are HCV antibody positive. However, routine screening of patients and staff is not recommended because transmission is unlikely when body substance precautions are applied and unlike Hepatitis B virus, there is no vaccine available at this time.

Mode of Transmission

With universal blood screening for anti-HCV, blood products are currently very safe (the risk of transmission from a blood unit is felt to be less than 1:7,000 per unit of blood. The major current risk of HCV transmission is intravenous drug use, however, in approximately 40% of HCV infections, a defined risk factor cannot be identified. The risk of sexual, horizontal and vertical transmission is generally very low and considered to be , < 5%. The risk of HCV transmission from a needlestick injury is also felt to be < 5%.

Incubation Period

usually 12-26 weeks, but it may be prolonged in immunosuppressed individuals

HCV antibody can be detected between 5-24 weeks (average 15)

this antibody is not protective, does not indicate immunity and is in fact, a marker for infectivity.

Active HCV infection can be confirmed by detecting HCV specific nucleic acids (RNA) by the polymerase chain reaction in serum.

Treatment

there is no vaccine available to prevent infection at this time.

Interferon has been used to treat chronic hepatitis C with a 15-25% sustained response rate. Newer Interferon type agents and other drug combinations are under investigation.

Prevention of all blood-borne pathogen transmission

Adherence to body substance precautions and other infection control practices

the appropriate personal protective equipment (goggles, masks, face shields, gloves etc) must be worn during high risk procedures

prompt thorough cleaning and disinfection of surfaces and equipment contaminated with blood or other potentially infectious fluid must be done using a 1:100 dilution of household bleach or a hospital approved high level disinfectant.

items grossly soiled with blood are considered to be biohazard and discarded in an appropriate manner (yellow bag)

care must be taken if multi-dose vials are used, such as Xylocaine, to avoid re-entering the vial with a used needle, and should be used for one patient only or dated when opened.

References:

1. Centers for Disease Control and Prevention: Guidelines for prevention of transmission of human immunodeficiency virus and hepatitis B virus to health care and public safety workers. MMWR 38 (S-6):1-37, 1989.

2. Rutala WA, Schafer KM: APIC Guideline for election and use of disinfectants. In Olmstead RN, editor: APIC infection control and applied epidemiology: principles and practice / Association for Professionals in Infection Control and Epidemiology, Inc., St. Louis, 1996, Mosby-Year Book, Appendix D

Guest Editor Dr. Mel Krajden

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