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Not Your Average Virus
By Charlene Buckner, RN, CIC, COHN-S, and Ann Drake, RN, CIC
Hepatitis C virus (HCV) infection is the most common form of chronic liver disease inthe US. The chronic liver inflammation caused by this virus is estimated by the CDC toaccount for approximately 10,000 deaths each year. Because of the sheer volume of reportedcases, about four million, and subsequent public interest, the broad clinical features andimplications of this disease merit review.
At this time, it appears that the greatest risk factor, by far, is injecting-drug use.Since 1992, routine blood donor screening for HCV antibodies has identified potentialcases and markedly reduced transmission via blood transfusion. As with other bloodbornepathogens, healthcare workers are at increased risk to percutaneous exposure due to thenature of their occupation. This fact has fueled the drive for safer sharps and needledevices and supporting legislation in some states, including recently Ohio. Infrequently,transmission has occurred from an infected mother to infant at childbirth and by exposureto multiple sexual partners. Hemophiliacs that received clotting factors before 1987, andpatients that received blood transfusions before 1990 are also at risk. Since 10% of thechronic dialysis patients are estimated to be infected with HCV, the staff in chronichemodialysis units should routinely take measures to minimize contamination of suppliesand equipment that could lead to transmission of HCV or other bloodborne pathogens.
Repeated or large volume percutaneous blood exposure is the most common route ofexposure. The approved screening test is the enzyme immunoassay (EIA), which detects theanti-HCV antibodies on average 8 to 10 weeks post exposure. The incubation period rangesfrom two to six weeks, but viral replication can be detected as soon as one week afterexposure by polymerase chain reaction (PCR), which is not an FDA approved test at thistime. Confirmation can be verified by the recombinant immunoblot assay (RIBA) test. Up to70% of the infected persons are asymptomatic. Those seeking medical care typically presenthepatitis symptoms such as jaundice, fatigue, appetite loss, and abdominal pain. Labvalues indicating elevated bilirubin and fluctuating aminotransferase (ALT) levels, aliver enzyme found in the blood when there is liver damage, can be demonstrated in about80% of this population. Only about 15% to 25% of these patients recover fully; theremainder develop chronic HCV infection. Of those with chronic HCV infection, 30% to 40%have normal liver enzymes and no symptoms. Of the asymptomatic patient population withelevated liver enzymes, 10% to 20% develop cirrhosis or hepatocellular carcinoma.
No clinical features or risk factors appear to create a reliable profile of progressionto severe chronic disease. However, some data indicate that certain behavioral anddemographic activities may increase the risk of chronic infection. These factors includeage over 40 years, male gender, daily alcohol ingestion, and repeated percutaneousexposure to blood, especially injection drug use. Co-infection with other infectiousdisease, such as HIV and HBV, appear to contribute to the development of cirrhosis andchronic disease. It is not unusual for two decades or more to pass before symptoms ofchronic infection appear, so years of "living clean" do not eliminate thepossibility of disease development due to youthful indiscretion.
Between 1988 and 1994, the National Health and Nutrition Examination Survey (NHANES)randomly selected almost 34,000 US citizens for the purpose of conducting basic history,physical, and laboratory examinations. The homeless and incarcerated were not included inthis sample. The prevalence of HCV chronic infection in this representative sample of thegeneral population was 1.8% (3.9 million people). In addition to the risk factors anddemographics already mentioned, HBV patients were more than six times more likely to alsohave HCV. The annual US mortality rate of approximately 10,000 deaths from HCV chronicliver disease is expected to triple in the next 10 to 20 years.
Currently, there is no vaccination available for HCV infection. Interferon has beenused to treat chronic disease in the patients that are at greatest risk to developcirrhosis. In the instance of relapse, the same drug has been used in combination withribavirin with some success. The ultimate therapeutic procedure is liver transplant, whichalso has limited long-term success rates. Therefore, the search for effective treatmentmodalities and preventive measures is intense.
The healthcare worker who has contact with blood is placed at risk for exposure tohepatitis C in the same manner as for hepatitis B and HIV. Over the years, the risk tohealthcare workers for contracting hepatitis B has been evaluated extensively in newinfections. Much less has been documented about the risks for workers exposed to hepatitisC. Reasons for this include the lack of laboratory markers for identifying exposed workersand the feeling that HCV was not spread efficiently through occupational exposure.
Currently, the estimated prevalence rates for HCV among healthcare workers is about 1%less than the national average of 1.8%. This should not detour one into a false sense ofsecurity. Because there is not a vaccine available, even a low risk for infection (<3%)may result in hundreds of infected workers. OSHA's 1991 Bloodborne Pathogen Standardrequired employers to establish a program to protect workers at risk from infection withhepatitis C as well as hepatitis B and HIV. The program includes an orientation for newemployees with discussion of the diseases, their signs and symptoms, and health outcomes.The plan also includes engineering controls, personal protective equipment, and therequired use of universal precautions. The standard has benefited employees by greatlyreducing their risk of exposure to all bloodborne pathogens.
To comply with OSHA's standard, employers should have policies and proceduresaddressing the post-exposure follow-up evaluation for any worker suffering a needlestickor mucosal exposure to human blood or other potentially infectious material.
If a worker suffers an exposure, the evaluation should be performed as soon aspossible. The healthcare worker should be tested for baseline information relative totheir HBV, HCV, and HIV status as well as the source individual unless their status isalready known.
Presently, there are not recommendations for prophylaxis with any anti-viral agents.The worker should be informed that there is a 2 to 3% risk of infection. He or she mightalso have concerns about personal issues such as sex or pregnancy that require answersfrom a qualified healthcare professional.
If the worker becomes infected, additional information should be provided that includesthe risk for alcohol and drugs increasing the liver damage, recommending vaccination forHBV and HAV, and a discussion of the risks associated with some alternative cures such asherbs or vitamins. Although most infected individuals will manage to live normal lives andeventually die of other causes, it is advisable that they have regular check-ups by aphysician familiar with the disease. In many parts of the country, there are supportgroups that can help keep those infected current on issues and treatments. In the eventthat your region does not have such a group, access to on-line services such as theHepatitis Information Network (www.hepnet.com) can also be a valuable resource.
The risk of transmission to a patient appears to be very low. The HCW should not berestricted from duty during the test period nor should the worker with a confirmedpositive HCV infection. Instead, the employee should be instructed to follow strictaseptic technique with the use of good handwashing adherence to universal precautions.Some states have policies requiring infected HCWs any bloodborne infections reporting totheir employers or other governing boards. The employee is advised to check forrequirements in their state.
It is advisable that employees understand the importance of reporting any exposuresthat occur. Complications from an infection with Hepatitis C might take years to develop,and well-documented exposures will expedite compensation claims. Since workers change jobsand places of employment move or merge, the worker should also keep copies of any reportthey make in their own home files.
Prevention remains the cornerstone in managing hepatitis C. An ongoing educationaleffort for the general public as well as targeted groups, such as healthcare workers, willraise awareness and ultimately reduce the numbers of new cases of chronic infections.Future costs to society for drug therapies and transplants for those with chronic HCVinfections cannot be predicted easily. However, we know that current drug therapy can costover $1,000 per month and liver transplants over $100,000. Diagnostic tests, such aslaboratory tests and liver biopsies, will also add to the financial burden that all of uswill share.
The effort to control this infectious disease must be supported by the public andprivate sector. Education, management of existing cases, and research into new drugs andtherapies are needed. Financial resources must be found to fund these endeavors. It shouldbe apparent that HCV is not just an average disease but one that requires exemplaryaction.
Charlene Buckner, RN, CIC, COHN-S, and Ann Drake, RN, CIC, are Infection DiseaseConsultants for the Ohio Department of Health (Columbus, Ohio).
For a list of references, access the ICT Web site.
Table 1: Estimated average prevalence of HCV infection in the US by variouscharacteristics and estimated prevalence of persons with these characteristics in thepopulation.
|Characteristic||HCV-infection prevalence||Prevalence of persons with characteristic, %|
|Persons with hemophilia treated with products made before 1987||87||(74-90)||< 0.01|
|Injecting-drug users current||79||(72-86)||0.5|
|history of prior use||No data||--||5|
|Persons with abnormal alanine amino trasferase levels||15||(10-18)||5|
|Chronic hemodialysis patients||10||(0-64)||0.1|
|Persons with multiple sex partners (lifetime) >50||9||(6-16)||4|
|Persons reporting a history of sexually transmitted diseases||6||(1-10)||17|
|Persons receiving blood transfusions before 1990||6||(5-9)||6|
|Infants born to infected mothers||5||(0-25)||0.1|
|Men who have sex with men||4||(2-18)||5|
|Volunteer blood donors||0.16||--||5|
For a complete list of references click here