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A recent report from BBC
News outlined in very simple terms some of the procedures
involved in vaccine production, which most people are completely
unaware of. Very likely, most people have
an "out of sight - out of mind"
mentality when it comes to vaccines. All they see
is a clear liquid in a syringe and they don't want to know
what is really in there or how it got there.
Particularly surprising to many people might be the wide
use of animal-based ingredients used to mass-produce vaccines.
This has caused some problems is the past and continues today.
Recently, a "scare" has arisen in Europe when it
was discovered that some polio vaccines
were made using cells from calf fetuses
that were possibly infected with BSE (Mad Cow disease).
This type of scare is not a new phenomenon. Back in the 1950's
it was discovered that polio vaccines contained a monkey virus
known as Simian Virus 40 (SV40). Millions were given the contaminated
vaccines before it was replaced. Now there are reports that
SV40 is turning up in human cancers.
Virus Nurseries
One of the main uses of animal cells is as "nurseries"
for the modified viruses that constitute the main or "active"
ingredient of a vaccine.
The animal cells serve as medium in which the virus in question
will replicate and produce more copies of itself.
Scientists have various "cell lines", which are
"immortal" cells that can keep on dividing indefinitely.
These cells are derived originally from a variety of animal
and human sources, including monkeys, hamsters,
chicken fetuses or even human
fetuses.
Vaccine Soup
However, this is not the only use of animal-derived substances.
The virus-infected cells are bathed in a "soup"
made up of ingredients such as glucose for energy, and other
chemicals such as growth factors, which can help the cells
to develop faster.
Although human growth factors can be extracted, these do
not provide as reliable or cost-effective results as other
sources, such as fetal calf serum,
which is widely used.
Dr Deborah Scopes, a spokesman for the British Society of
Immunology, said of the vaccine 'soup': "It's a big broth
which helps growth."
Once sufficient numbers of the virus have been replicated,
the manufacturers use complex filtration and purification
processes to try to remove as much of the substances other
than the viruses from the vaccine.
"You don't want to produce an immune response to cow
tissue - you want to produce the biggest immune response possible
to the viruses, to make the vaccine effective," said
Dr. Scopes
BBC News, October 20, 2000
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