FAQS
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Definition
of the disease
Hepatitis
B is one of the major diseases of mankind and is a serious
global public health problem. It is preventable with
safe and effective vaccines that have been available
since 1982. Of the 2 billion people who have been infected
with the hepatitis B virus (HBV), more than 350 million
have chronic (lifelong) infections. These chronically
infected persons are at high risk of death from cirrhosis
of the liver and liver cancer, diseases that kill about
one million persons each year. Although the vaccine
will not cure chronic hepatitis, it is 95% effective
in preventing chronic infections from developing, and
is the first vaccine against a major human cancer. In
1991, the World Health Organization (WHO) called for
all children to receive the hepatitis B vaccine, and
116 countries have added this vaccine to their routine
immunization programmes. However, the children in the
poorest countries, who need the vaccine the most, have
not been receiving it because their governments cannot
afford it. Fortunately, hepatitis B vaccine will soon
be available in these countries with the assistance
of the Global Alliance for Vaccines and Immunization
(GAVI) and the Global Fund for Children's Vaccines.
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Transmission
Hepatitis
B virus is transmitted by contact with blood or body
fluids of an infected person in the same way as human
immunodeficiency virus (HIV), the virus that causes
AIDS. However, HBV is 50 to 100 times more infectious
than HIV.
The
main ways of getting infected with HBV are:
- Perinatal
(from mother to baby at the birth);
- Child-
to-child transmission;
- Unsafe
injections and transfusions;
- Sexual
contact.
Worldwide,
most infections occur from infected mother to child,
from child to child contact in household settings, and
from reuse of unsterilized needles and syringes. In
many developing countries, almost all children become
infected with the virus.
In
many industrialized countries (e.g. Western Europe and
North America), the pattern of transmission is different.
In these countries, mother-to-infant and child-to-child
transmission accounted for up to one third of chronic
infections before childhood hepatitis B vaccination
programmes were implemented. However, the majority of
infections in these countries are acquired during young
adulthood by sexual activity, and injecting drug use.
In addition, hepatitis B virus is the major infectious
occupational hazard of health workers, and most health
care workers have received hepatitis B vaccine.
Hepatitis
B virus is not spread by contaminated food or water,
and cannot be spread casually in the workplace.
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Symptoms
Hepatitis
means inflammation of the liver, and the most common
cause is infection with one of 5 viruses, called hepatitis
A,B,C,D, and E. All of these viruses can cause an acute
disease with symptoms lasting several weeks including
yellowing of the skin and eyes (jaundice); dark urine;
extreme fatigue; nausea; vomiting and abdominal pain.
It can take several months to a year to feel fit again.
Hepatitis B virus can cause chronic infection in which
the patient never gets rid of the virus and many years
later develops cirrhosis of the liver or liver cancer.
HBV is the most serious type of viral hepatitis and
the only type causing chronic hepatitis for which a
vaccine is available.
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Prevalence
- who is at risk?
In
much of the developing world, (sub-Saharan Africa, most
of Asia, and the Pacific), most people become infected
with HBV during childhood, and 8% to 10% of people in
the general population become chronically infected.
In these regions liver cancer caused by HBV figures
among the first three causes death by cancer in men.
High
rates of chronic HBV infection are also found in the
Amazon and the southern parts of Eastern and Central
Europe. In the Middle East and Indian sub-continent,
about 5% are chronically infected. Infection is less
common in Western Europe and North America, where less
than 1% are chronically infected.
Young
children who become infected with HBV are the most likely
to develop chronic infection. About 90% of infants infected
during the first year of life and 30% to 50% of children
infected between 1 to 4 years of age develop chronic
infection. The risk of death from HBV-related liver
cancer or cirrhosis is approximately 25% for persons
who become chronically infected during childhood.
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Treatment
Liver
cancer is almost always fatal, and usually develops between
35 and 65 years of age, when people are maximally productive
and with family responsibilities. The loss of a mother
or a father in a developing country can devastate the
entire family. In developing countries, most people with
liver cancer die within months of diagnosis. In industrialized
countries, surgery and chemotherapy can prolong life up
to a few years. Chronic hepatitis B in some patients is
treated with drugs called interferon or lamivudine,
which can help some patients. However, interferon
or lamivudine therapy costs thousands of dollars
and will never be available to most patients in developing
countries. Patients with cirrhosis are sometimes given
liver transplants, with varying success. It is preferable
to prevent this disease with vaccine than to try and cure
it.
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Vaccine
Hepatitis
B vaccine has an outstanding record of safety and effectiveness.
Since 1982, over one billion doses of hepatitis B vaccine
have been used worldwide. The vaccine is given as a
series of three intramuscular doses. Studies have shown
that the vaccine is 95% effective in preventing children
and adults from developing chronic infection if they
have not yet been infected. In many countries where
8% to 15% of children used to become chronically infected
with HBV, the rate of chronic infection has been reduced
to less than 1% in immunized groups of children.
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How
is WHO trying to control Hepatitis B?
Since
1991, WHO has called for all countries to add hepatitis
B vaccine into their national immunization programmes.
As of March 2000, 116 countries had included hepatitis
B vaccine in their national programmes including most
countries in Eastern and South- East Asia, the Pacific
Islands, Australia, North and South America, Western
Europe and the Middle East. However, many low income
countries in sub-Saharan Africa, the Indian subcontinent
and in the Newly Independent States do not use the
vaccine. The price of the hepatitis B vaccine has
been one of the main obstacles to its introduction
in many of these countries.
The
Global Alliance for Vaccines and Immunization (GAVI)
was created in 1999. It is a unique coalition of public
and private institutions where WHO has taken a leading
role. The main mission of GAVI is to vaccinate as
many children as possible against vaccine-preventable
diseases. GAVI has introduced a new approach to international
health funding: the Global Fund for Children's vaccines
(GFCV). This fund will help 74 low-income countries
to reinforce their national vaccine programmes and
introduce hepatitis B, yellow fever and haemophilus
influenzae type b(Hib) vaccines into their national
immunization programmes.
Source:
WHO
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