- The 'Lectric Law Library Presents Hepatitis C - A Silent
- From Dr. Steven E. Lerner & Associates*
- The estimated number of new hepatitis C virus (HCV) infections
annually in the United States is approximately 150,000 although the true
incidence is probably greater. Screening of healthy blood donors indicates
that the minimum prevalence of chronic HCV infection is 1 per 200 in this
low-risk population. The true prevalence may be closer to 1.0 - 1.5%. An
estimated 3 - 3.5 million Americans are carriers of the hapatitis C virus.
- Transmission of Virus
- Transfusion of blood products used to be the primary
source of transmission of the virus. Use of volunteer donors and screening
of blood for the antibody to the virus has reduced the risk of acquiring
hepatitis C from a transfusion to 1 per every 3000 units of transfused
blood. Currently only 4% of patients with chronic HCV acquire the infection
by blood transfusion, hence screening of transfused blood for HCV contamination
is unlikely to reduce the prevalence of chronic HCV.
- Thirty-eight percernt of chronic HCV infections are due
to intravenous drug use, 1% are dialysis patients, 10% are patients with
a history of sexual contacts or a household contact with someone with hepatitis
C. Although 30 - 45% of infected patients deny any discernible risk factors
for the disease, many of these individuals have histories of high risk
behaviors such as multiple sexual partners, illicit non-intravenous drug
use or prior imprisonment.
- Occupational Hazard
- Hepatitis C is a known occupational hazard. Two percent
of cases of hepatitis C are due to occupational percutaneous exposures,
mostly in the form of needle sticks in health-care workers. The risk of
acquiring the virus from a single needle stick from an infected individual
is estimated to be approximately 10%. There have been numerous studies
of the prevalence of hepatitis C in different health-care populations.
Some groups such as oral surgeons who are often exposed to aerosolized
blood may have a prevalence of HCV as high as 10%, 4 - 6 times the national
average. Dialysis and operating-room nurses are higher risk than non-surgical
hospital personnel with prevalences ranging from 1.5 to 4%.
- The majority of infections with HCV are clinically silent.
The infected individual may have no symptoms for 30 - 40 years. The infection
is often discovered accidentally during routine physical examinations or
during applicaitons for life insurance. The disease will occasionally present
as new-onset liver failure or liver cancer.
- The natural history of chronic HCV disease is still being
defined. The virus has only been identified and sequenced within the last
four years. It is generally accepted that 20 - 30% of patients with chronic
HCV will progress to cirrhosis (scarring and malfunction of the liver),
and liver cancer develops in about one fifth of patients with cirrhosis.
The slowly progressive nature of this disease is apparent from a retrospective
study of post-transfusion HCV showing that chronic hepatitis, cirrhosis
and liver cancer developed after a mean of 10, 21 and 29 years respectively.
Once cirrhosis develops the risk of liver cancer is from 3 - 6% per year.
HCV accounts for 25% of patients undergoing liver transplantation.
- The best current data suggest that the risk of developing
clinical liver failure is 5 - 15% and the risk of dying from liver-related
complications 3 - 9%. Conversely, 80 - 90% of infected individuals will
probably live normal life spans without symptomatic liver disease.
- Can HCV Infection be Treated?
- The goad of anti-hepatitis C therapy is to ameliorate
symptoms and halt the progression of disease to cirrhosis and possible
liver cancer. Alpha2b-Interferon was licensed for the treatment of chronic
hepatitis C in 1991. It is the only agent which has shown efficacy against
the virus. Although 40 - 50% of patients respond to a 6 month course of
treatment with normalization of liver enzyme levels, the relapse rate after
therapy is at least 50% and as high as 80%. Unfortunately, three to four
years after successful interferon treatment only 8 - 15% remain free of
virus and have normal liver function tests.
- Interferon therapy is associated with considerable morbidity.
It must be administered subcutaneously. At the beginning of therapy 60
- 80% of patients have a flu-like illness which resolves within three weeks.
Additional side-effects include irritability, fatigue, depression, anorexia,
nausea, rashes and hair loss. Migraine headaches may increase in severity
and frequency. A history of anxiety or depressive illness is a relative
contraindication to interferon treatment.
- At current Food and Drug Administration approved dosing
85 - 92% of treated patients will not ultimately benefit from interferon
treatment. Since the best current estimates are that clinically significant
disease will occur in only 5 - 15% of infected individuals, the vast majority
of infected individuals will not benefit from interferon therapy. Assuming
a "cure" rate of 8 - 15% in the 5 - 15% who would potentially
benefit from treatment, one comes to an estimated improvement in outcome
in only 0.4 - 2.25% of patients. Even this higher number is doubtful since
the group with the most aggressive disease tends to have the lowest response
- Recent studies indicate that a mere six months of treatment
at three million units may be suboptimal. Treatment with high doses (up
to 30 million units per week) for 12 - 18 months have produced "cures"
in 22 - 45%. To get sustained remission in over 50% of patients on a consistent
basis may require several years of interferon therapy.
- In summary HCV infection is a serious viral epidemic
affecting 1.5% of the United States population. Health-care personnel are
at risk for occupational exposure, especially those exposed to blood products
on a regular basis such as dialysis and operating room nurses. Although
treatment is available it is associated with considerable expense and morbidity
and fails to cure the disease in up to 90%. The infection can lead to liver
failure and liver cancer in a substantial minority of infected individuals.
The disease is becoming an important issue in workers compensation for
health-care employees. Extensive research is underway in an attempt to
develop more effective therapies.
- * This article is presented and copyrighted by The 'Lectric
- and Dr. Steven E. Lerner & Associates (www.drlerner.com)
- Patricia A. Doyle, PhD
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