| The
most common causes of chronic hepatitis world wide are
hepatitis viruses. The vast majority of viral hepatitis
cases seen in the United States are caused by one of
the six human hepatitis viruses (A, B, C, D, E and G).
These differ in genome structure, mode of transmission
and natural history of the disease they cause. Of these
six, only B, C and D are known to cause chronic liver
disease accounting for 60-80% of chronic hepatitis. The
hepatitis C virus was discovered in 1988 and was the
cause of more than 90% of the cases that were called
non-A, non-B hepatitis.
Hepatitis C virus is:
 A
single stranded RNA virus, which is a member of the
Flaviviridae family.
The
RNA genome that is 9,400 nucleotides in length and
codes for a polyprotein of 3,010 to 3,030 amino acids.
Characterized
by significant genetic variation within and between
isolates.
A
virus that has six major genotypes given numerical
names 1-6.
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The Importance of HCV
The importance of chronic infection with hepatitis
C is greater than generally recognized. Most
of the HCV infected individuals are not aware of their
disease because they are not clinically ill, which
makes it a Silent Epidemic.
According to the Centers for Disease Control and Prevention
(CDC) chronic hepatitis C infection is:
The
most common chronic bloodborne infection in the United
States.
Four
times more common than HIV.
More
than 4 million people in the United States infected.
More
than 270,000 patients are living in Florida alone.
The
cause of 230,000 new cases annually in the United States.
10th
leading cause of death.
The
cause of 40% of chronic liver disease.
Most
frequent indication for liver transplant. (1/3
of transplants)
Costs
over $600 million each year.
Patients are infrequently diagnosed until the development
of complications because most of the acute and chronic
hepatitis C patients are asymptomatic. Less than 1/3rd of
the acute infections are clinically apparent cases
that may be severe enough to come to medical attention.
The majority (85%) of the patients acquiring hepatitis
C (unlike hepatitis B) never clear the virus completely
and out of these, 60% will progress to complications
like Cirrhosis, Hepato-cellular Carcinoma, liver failure
and death.
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Epidemiology: Burden
and Prevalence of HCV
Hepatitis C virus was discovered in 1988 and was the
most common cause of non-A, non B hepatitis in the
United States and worldwide. According to the Centers
for Disease Control and Prevention (CDC), in the United
States the annual occurrence of new hepatitis C infections
has declined from a high of 180,000 annually in the
mid 1980’s to about 28,000 in 1995. This decreased
occurrence is probably due to:
Improved
awareness and dangers of sharing needles.
Elimination
of blood donations from high risk donors.
Sensitive
serologic tests used in blood banks.
Although
the incidence of newly infected HCV is declining, the prevalence is
expected to triple in the next 10 -20 years. Individuals
infected 10-20 years ago have no signs or symptoms,
but are now being diagnosed because of increased awareness
and testing. Additionally, individuals infected
20 or 30 years ago are now becoming symptomatic with
chronic liver disease, cirrhosis, and liver failure.
Currently there are 4 million Americans chronically
infected with hepatitis C and this translates into
more than 270,000 patients in Florida alone. HCV infection
results in 8,000 – 10,000 deaths in the United
States every year. This number is expected to triple
in the next 10-20 years, and it is projected that more
deaths will be attributable to complications from HCV
than to HIV.
In the general population HCV affects persons of all
ages, and all racial and ethnic groups at a prevalence
rate of 1.8%. The occurrence of new HCV infections
is most common in:
persons
aged 20-39 and is higher in males and Hispanics,
but is the same in whites and blacks.
persons
aged 30-49 and in males.
African
Americans have a substantially higher prevalence than
the whites. The prevalence increases until age 40 in
whites and age 50 in blacks, suggesting there is a
large reservoir of chronically infected relatively
young Americans who are at risk of developing chronic
liver disease and act as a source of new infections
to others.
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How do hepatitis and
HIV viruses compare?
HIV
and hepatitis C remain dormant for many years (15–20
years in case of HCV) before symptoms start to appear.
Like
HIV, the majority (85%) of HCV patients never clear
the virus completely from their system and 60% will
progress to complications like cirrhosis, hepatocellular
carcinoma, liver failure and death.
Like
HIV, there is no vaccine available for hepatitis
C, where as both vaccines and immune globulins are
available for hepatitis A & B.
Like
HIV, hepatitis C infection is a prolonged illness
which is initially asymptomatic and requires a high
index of suspicion on the part of the health provider
to identify the patients with risk factors and counsel
them to be tested.
Like
HIV, hepatitis C infected patients need to be identified
early and referred for life long management.
Like
HIV, the treatment is complex and prolonged and most
often results in reducing inflammation and complications
but not in cures.
Like
HIV, all patients with hepatitis C are potentially
infectious.
Like
HIV, good nutrition, vitamins and a healthy life
style help.
Hepatitis A, hepatitis B and HIV are similar to HCV
in that:
They
are all caused by virus infections.
There
are no antibiotics for a cure.
They
are caused by risky conditions.
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Conclusion
Approximately 1.8% of Americans are infected with
hepatitis C Virus (HCV). Many of them are unaware that
they are infected, and are at-risk of chronic liver
disease and can spread it to others. Some of them are
probably your patients and when you take a history,
consider whether they are at-risk for hepatitis C.
Most patients with HCV infection will be infected for
life and most will have chronic liver disease.
Infected patients will need advice on how to minimize
damage to their livers and how to prevent spreading
HCV to others. To protect their livers you should tell
them to not drink alcohol, to get vaccinated against
hepatitis A and B, to not eat raw seafood and to not
use illegal and recreational drugs in any form. To
protect others from contact with their blood you should
tell them to not donate blood, organs, tissues or semen.
If they shoot drugs, tell them to stop it and get into
a treatment program. If they can’t stop, at least
use a clean needle and do not share it with others.
Also they should not share their toothbrushes, razor
blades and other personal care items that could have
blood on them. And, don’t forget to advise them
to practice safer sex.
Finally, one more thing to do for these patients is
to put them in contact with local organizations that
can help them deal with their concerns and fears.
In summary Chronic hepatitis C is a progressive disease,
which is associated with substantial morbidity and mortality.
It is very important that such patients are identified
and evaluated before severe liver disease develops, as
treatment is available. Early interventions may result
in prevention of spread to others and may delay the progression
to chronic liver disease.
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A timeline to
the discovery of HCV |
Year |
Event |
| 1960's |
Risk
of transfusion-associated hepatitis exceeds 20% |
| 1970s |
Non-A, non-B hepatitis identified
because 90% of transfusion-associated hepatitis
was not caused by hepatitis A or hepatitis B. Use
of all-volunteer blood donors and hepatitis B testing
reduces risk for transfusion-associated hepatitis
to 10%. |
| 1980s |
Twenty percent of acute community-acquired
hepatitis caused by non-A, non-B hepatitis. Other
risk factors identified, including injecting drug
use, occupational exposure to blood, and sexual
exposure to infected partner or to multiple partners. |
| 1986-1987 |
Surrogate testing of blood donors
for non-A, non-B hepatitis implemented using ALT
and hepatitis B core antibody. Risk for transfusion-associated
hepatitis declines to 1.5% per recipient or 0.02%
per unit transfused by 1990. |
| 1988 |
Hepatitis C virus (HCV) discovered
by molecular cloning. |
| 1989-1990 |
Ninety percent of transfusion-associated
and community-acquired acute and chronic non-A,
non-B hepatitis caused by HCV. |
| 1990 (May) |
FDA approves first HCV antibody (anti-HCV)
test, and routine testing of blood donors is implemented. |
| 1991 |
Guidelines for screening donors of
blood, plasma, organs, tissues, and semen for evidence
of hepatitis B and hepatitis C issued by United
States Public Health Service. |
| 1991 |
FDA approves alpha-interferon for
use in the treatment of patients with chronic hepatitis
C. Therapy eliminates virus and reduces liver injury
in 10% to 20% of persons treated. |
| 1992 |
Studies show that most HCV-infected
persons develop chronic infection and chronic liver
disease. Forty percent of chronic liver disease
in the US estimated to be HCV-related. |
| 1992 |
FDA approves the more sensitive second
version anti-HCV test. Risk for transfusion-associated
HCV infection is reduced to 0.001% per unit transfused. |
| 1993 |
FDA approves a supplemental (confirmatory)
test for anti-HCV that distinguishes between true
and false positive results. |
| 1993-1996 |
HCV infection found in up to 90%
of injecting drug users and persons with hemophilia
treated with clotting factor concentrates before
effective procedures to inactivate HCV were introduced,
and in an average of 20% of long-term hemodialysis
patients. Risk for HCV infection found to be 5%
among infants born to infected mothers and 2% among
health-care workers after exposure to HCV positive
blood from accidental needlesticks. |
| 1996 |
FDA approves the third version anti-HCV
test. |
| 1996 |
CDC's Third National Health and Nutrition
Examination Survey (1988-1994) shows that an estimated
3.9 million Americans have been infected with HCV. |
| 1997 |
NIH Consensus Conference on the diagnosis,
management, and treatment of hepatitis C. |
| 1997 |
CDC begins a national program to
educate health care professionals about the diagnosis,
medical management and prevention of HCV infection. |
| 1998 |
FDA publishes guidance for the notification
of persons who received blood or blood products
that were potentially infectious for HCV. |
| 1998 |
"Recommendations for Prevention
and Control of Hepatitis C Virus (HCV) Infection
and HCV-Related Chronic Disease"
is published in MMWR. |
| 1998 |
New HCV infections have decreased
by over 80% since 1990. |
| 1998 |
FDA approves combination antiviral
therapy using interferon and ribavirin for patients
with chronic hepatitis C. Combination therapy eliminates
virus and reduces liver injury in 30% to 40% of
persons treated. |
| 1999 |
Targeted and general notification
programs begin to encourage transfusion recipients
and others at risk for HCV infection to seek counseling
and testing. |
| Source: Centers for Disease
Control and Prevention |
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