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The Issue
The Virus
Transmission
Infection
Healthcare Workers and Exposures
Treatment
Prevention
Summary
Additional Resources
The Updated U.S. Public Health Service Guidelines for the Management of Occupational Exposures to
HBV, HCV, and HIV and Recommendations for Postexposure Prophylaxis, published in June 2001,
provides the scientific basis for OSHA’s regulations and forms the basis for OSHA’s
enforcement of the Standard. The first recommendation in a recently released consensus statement of a
panel of experts is to educate the American public on the transmission of the hepatitis C virus (HCV)
in order to better identify afflicted individuals and institute preventive measures. As occupational
health providers, it is not only our responsibility to be fully informed on this virus in order to
treat those patients who experience bloodborne pathogen exposures, but also to educate our clients
and patients on prevention of this disease. A recent possible exposure was announced in June of this
year when a hospital declared it was notifying 268 patients of a possible risk of exposure to
hepatitis B and hepatitis C from the use of a flexible nasal pharyngoscope. The scope was possibly
contaminated in the shipping case. The possible exposures occurred during procedures performed
between 2000 and 2001.
The Issue
The hepatitis C virus is the leading cause of known liver disease in this country. It is the most
common cause of cirrhosis, hepatocellular cancer (HCC), and the need for liver transplants. It is
reported that there are at least 4 million people in this country believed infected with this virus.
Yet there are many people in the United States that don’t even know they have the virus because
they are not clinically ill and have never had reason to be tested. The Centers for Disease Control
and Prevention (CDC) estimates that HCV is responsible for 8,000 to 10,000 deaths per year in this
country. Of particular interest to occupational health providers, current estimates of medical and
work-loss costs of HCV-related acute and chronic liver disease are in excess of $600 million
annually. There is some good news to report. The CDC staff estimates that during the 1980s there were
an average of 242,000 new infections per year. Currently that figure is estimated to have fallen to
35,000 acute HCV infections a year. However, because of the high rate of persistent infection, a
four-fold increase in the number of people with chronic HCV infection is projected from 1990 to 2015.
HCV is reported to be the most common bloodborne infection in the United States. Persons aged
40–59 years have the highest prevalence of HCV infection, with a higher prevalence among the
African-American population.
The Virus
Originally categorized in 1974 as “non-A, non-B hepatitis,” the hepatitis C virus,
discovered in 1989, was found to be responsible for the majority of those cases. HCV is an RNA virus
of the Flaviviridae family, which has a high propensity to mutate. There are 6 HCV genotypes and more
than 50 subtypes.
Because of the lack of a vigorous T-lymphocyte response, there appears to be a high rate of chronic
infection. The difficulty in developing a vaccine and the lack of response to therapy is believed to
be explained by the genetic heterogeneity of HCV.
Transmission
The primary transmission is from exposure to infected blood. The exposures result from:
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injection drug use
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blood transfusion
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solid organ transplants
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unsafe medical practices
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occupational exposure to blood
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multiple heterosexual partners
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high risk sexual partners
Blood transfusions, which accounted for a significant
proportion of HCV-related infections acquired more than 15 years ago, rarely account for recently
acquired infections. The highest seroprevalence rates (70–90%) are reported in those individuals
who use injected drugs; other high rates are among the homeless, prisoners, and
hemophiliacs.
Infection
After initial exposure, HCV RNA can be detected in blood in one to three weeks, and is present when
symptoms begin. Antibodies to HCV are detected by enzyme immunoassay (EIA) in only 50 to 70% of
patients at the onset of symptoms. Liver cell injury is manifested by the elevation of alanine
aminotransferase (ALT) within two to eight weeks. Symptoms are uncommon but can include weakness,
anorexia, fatigue, and jaundice. Symptoms usually subside after several weeks as ALT levels
decline.
Chronic HCV infection is diagnosed if the HCV RNA is detected at least intermittently in the blood by
qualitative or quantitative test for a period of at least six months. In general it is reported that
the majority of HCV-infected persons develop chronic infection during the first two or more decades
after the initial infection. Chronic HCV infection can lead to progressive liver fibrosis, which
leads to cirrhosis, end-stage liver disease, and liver cancer. The actual risk of progressive disease
after 20 years is believed to be 7–16% based on prospective studies. Factors observed to
increase the risk include older age at time of infection, male gender, an immunosuppressed state, and
alcohol use.
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Healthcare Workers and
Exposures
THealthcare workers are reported to have a higher prevalence of HCV infection than the general
population but some of this may be due to non-occupational sources. The risk of seroconversion from a
percutaneous exposure to blood from an HCV-positive source is 1.8%.
The importance of ordering the correct laboratory testing for HCV exposure is stressed, particularly
for healthcare workers who sustain bloodborne pathogen exposures. At this time, antiviral prophylaxis
is not recommended following needlestick exposure. If the source is negative, there is generally no
reason to test the exposed unless the goal is to find pre-existing hepatitis C.
Antibodies to HCV are detected by enzyme immunoassay (EIA). If the source is HCV EIA positive, an HCV
RNA assay should be done to detect the presence of HCV. The exposed individual should be tested for
HCV antibody and serum alanine aminotransferase (ALT) at exposure and repeated at 4–6 months.
An elevated ALT indicates liver cell injury. If seroconversion occurs, the recommendations for
treatment following acute HCV infection should be followed. An algorithm chart detailing the lab
testing process can be viewed here.
Treatment
Combining two therapies is the best way to treat hepatitis C, according to the draft consensus. The
combination includes PEG interferon, a protein that blocks virus reproduction, and the antiviral
medication ribavirin. The combination works well in about half of the patients treated for 48 weeks
with the most common form of the virus. A sustained viral response (SVR) of no detectable qualitative
HCV RNA in the serum by RT_PCR 24 weeks after the end of treatment is the best indicator of effective
therapy. There are side effects, ranging from flu-like symptoms to blood abnormalities and
depression. Patient education is important to manage these symptoms. Patients considered for
retreatment include those in whom HCV infection failed to achieve SVR.
Prevention
Because of the large number of individuals infected with HCV, there remains a source of transmission
to others at risk. While direct percutaneous exposure is the most efficient method for transmission
and accounts for two-thirds of all new infections, the majority of other cases are attributed to
sexual transmission and occupational exposures to blood. The actual risk of transmission from the
latter two is low. Needle and syringe exchange programs, use of condoms, awareness of perinatal
transmission, education, and adherence to OSHA’s bloodborne pathogen standard remain frontline
prevention activities.
Primary prevention strategies aimed at reducing the risk
of contracting HCV include:
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screening and testing of blood, plasma organ, tissue,
and semen donors;
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virus inactivation of plasma-derived products;
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risk reduction counseling and services;
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implementation and maintenance of infection control
practices.
Secondary prevention strategies aimed at reducing the risk
of liver and other chronic diseases in HCV infected persons include:
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identification, counseling, and testing of persons at
risk;
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medical management of infected persons.
Summary
We need to be aware of the latest findings and recommendations in the fight against this public
health threat. As occupational medicine providers, we are often the first line of defense for
healthcare workers after a needlestick injury. Our policies need to reflect the latest
recommendations. Our nurses and physicians should be informed in order to counsel the healthcare
workers treated in their clinics. We can join in the education effort by providing information via by
pamphlets or training sessions for designated clients.
Additional Resources
consensus.nih.gov
www.cdc.gov/mmwr/PDF/RR/RR5011.pdf
www.osha.gov
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