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.
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
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
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 to interferon.
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 Law Library
and Dr. Steven E. Lerner & Associates (www.drlerner.com)