[e-drug] Medicalisation - Hepatitis B vaccine safety (cont'd)

[Klara Tisocki <ktisocki@healthnet.zw>]

E-drug: Medicalisation - Hepatitis B vaccine safety (cont'd)
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I was horrified to read the sweeping statements by BUKO
Pharma-Kampagne and the insinuation of unknown facts about the
disease and the "definite" knowledge of harms caused by the
vaccine.

For the benefit of e-drug readers without internet access I enclose
here abridged info collected from WHO, CDC, etc. fact sheets and
other independent professional sites. For more detailed info of
safety of HBV vaccine read "Questions and answers about hepatitis
B infection and vaccine"
http://www.who.int/vaccines-diseases/safety/infobank/HepatitisB.s
html

Dr. Klara Tisocki
Department of Clinical Pharmacology
University of Zimbabwe
Medical School
PO Box A178
Harare, Zimbabwe
Tel: 263 4 707707 ext 2120
Fax: 263 4 790233
E-mail ktisocki@healthnet.zw
Mobile: 091 402 572

***************************************************
THE DISEASE
Hepatitis B is a serious disease caused by the hepatitis B virus
(HBV) which is present in the blood and body fluids of an infected
individual. The virus can be transmitted from mother to baby at
birth as well as through unprotected sexual intercourse, and
unsterilized needles. Hepatitis B is 100 times more infectious than
the HIV virus. Transmission is also possible with household
contacts and from child to child. HBV infection can cause acute
illness that leads to loss of appetite; tiredness; pain in muscles,
joints, or stomach; diarrhea or vomiting; and yellow skin or eyes
(jaundice). HBV can also cause chronic infection, especially in
infants and children, that leads to liver damage (cirrhosis), liver
cancer, and death.

LIVER CANCER
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. In developing countries, most people
with liver cancer die within months of diagnosis. In industrialised
countries, surgery and chemotherapy can prolong life up to a few
years only. Chronic hepatitis B in some patients is treated with
drugs called interferon or lamivudine, which can help some patients.
However, drug therapy is expensive and will not available to most
patients in developing countries. Patients with cirrhosis are
sometimes given liver transplants, with varying success (again
expensive and inaccesibale for most patients) . It is preferable to
prevent this disease with vaccine than to try and cure it.

THE STATISTICS
- Of the 2 billion people (1 in 3 world-wide) who have been infected
with the hepatitis B virus (HBV), more than 350 million have chronic
(lifelong) infections.
- These 350 million chronically infected persons are at high risk of
death from cirrhosis of the liver and liver cancer.
- Death from chronic liver disease occurs in 15-25% of chronically
infected persons
- Liver cancer kills about one million persons each year world-wide.
- 30-40% of people with HBV infection show no symptoms and can
unknowingly pass HBV to others.
- About 30% of HBV cases are related to heterosexual activity,
either unprotected sex with an infected person or multiple sexual
partners.
- Up to 90% of babies born to chronically infected mothers are
infected at birth if they do not receive the HBIG (Hepatitis B
Immune Globulin) and vaccine. 15- 25% of these children will die of
chronic liver disease, cirrhosis or liver cancer before they reach
middle age.
- There is a 6-30% chance of HBV infection from a single needle
stick contaminated with HBV.
- HBV can live on a dry surface for at least 7 days.

Without vaccination chronic infection (risk for liver cancer) occurs
in:
- 90% of infants infected at birth
- 30% of children infected at age 1-5 years
- 6% of persons infected after age 5 years

HEPATITIS B VACCINE
Hepatitis B vaccine prevents both HBV infection and acute hepatitis
B as well as the chronic consequences of HBV infection, including
cirrhosis and liver cancer. It has been available since 1982. Over
one billion doses of hepatitis B vaccine have been used world-wide.
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. As of March
2000, 116 countries had included hepatitis B vaccine in their
national immunisation programmes. Unfortunately many low income
countries in sub-Saharan Africa and the Indian subcontinent where
hepatitis B is highly endemic do not use the vaccine because they
cannot afford it.

THE BENEFITS
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 immunised groups of children. In
other words the risk of chronic infection is reduced by 88 - 93% in
immunised children compared to non-immunised children. HB
vaccine is the first vaccine against a major human cancer, that
causes serious disease and death, thus is a lifesaving preventative
intervention. Since it can take a long time for liver cancer to
develop in chronically infected patients it will be possibly to
measure accurately the benefits of HBV vaccination in reduction of
cirrhosis and cancer in immunised populations in the next two three
decades only.

THE RISKS
Hepatitis B vaccines have been shown to be very safe when given
to infants, children or adults. The most common side effects from
hepatitis B vaccination are pain at the injection site and mild to
moderate fever. Serious side effects reported after receiving
hepatitis B vaccine are very uncommon. While reported, there is NO
confirmed scientific evidence that hepatitis B vaccine causes
chronic illness, including multiple sclerosis, chronic fatigue
syndrome, rheumatoid arthritis, or autoimmune disorders.
Large-scale hepatitis B immunisation programs in Taiwan, Alaska,
and New Zealand have observed no association between
vaccination and the occurrence of serious adverse events.
Furthermore, surveillance of adverse events in the United States
after hepatitis B vaccination have not shown a clear association
between hepatitis B vaccine and the occurrence of serious adverse
events including Guillain-Barre' syndrome, transverse myelitis, optic
neuritis, and seizures. The presumed (not proven) risk of RARE
serious adverse events associated with hepatitis B vaccination must
be measured against the proven efficacy of the vaccination (95%
effective prevention) and the millions of lives and significant
morbidity from liver disease, it can save.

HBV vaccine, like other pharmaceutical products, are not entirely
risk-free. Rare serious adverse effects are often not evident until
vaccines come into widespread use and interpreting data from
vaccine safety research is often complex and is associated with
some uncertainty. Larger and longer randomised trials, updated
summaries of evidence, linked databases, prospective vaccination
registers, bar-coding of vaccines and standardisation of adverse
event definitions are necessary to address current questions.

Mass hysteria induced by anti-vaccine campaigning, leading to
reduced coverage with cellular DTP vaccine resulted in up to 100
fold increase in incidence of pertussis (millions of new cases of
pertussis, hundreds of deaths and thousands of complications) in
those countries where anti-vaccine movement could exert political
pressure on decision makers in spite of scientific evidence on
benefit and risks of DTP vaccination. (Good paper: Gangarosa et al.
Impact of anti-vaccine movements on pertussis control: the untold
story; Lancet 1998 351: 356-61).

Considering the high endemicity, high risk of transmission and
serious consequences of infection, reduction in HBV vaccination
can lead to millions of death and significant suffering. It is ironic
that western democracies invest billions of dollars in discovery of
new drugs to treat cancer (and indeed the millions of chronically
infected with HBV would need effective drug therapy) but at the
same time political pressure arising from inadequate interpretation
or misinterpretation of scientific evidence can jeopardise the
success of one the most cost-effective public health interventions -
immunisation (simple, cheap, no need for drugs, productive healthy
population saved, etc.)

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