WASHINGTON
(AP)--Cow-derived ingredients from mad cow-infected countries
are being replaced in certain vaccines as an extra precaution,
even though the government's top mad cow experts call any risk
theoretical.
The Food and
Drug Administration discovered last February that a few makers
of common childhood vaccines, from diphtheria to polio, had continued
using the ingredients for seven years after the FDA told them
to stop.
In July, the
FDA's scientific advisers publicly debated the issue and ``we
agreed any risk was very small,'' said panelist Dr. Peter Lurie,
a physician and consumer advocate. ``It's not like they used cow
cells in the final vaccines. ... It's complicated.''
As The Associated
Press reported this week, the vaccines are being reformulated
as a precaution.
To ensure
consumers understood the issue, FDA last year created an Internet
page stressing the vaccines are safe to use. The Centers for Disease
Control and Prevention reiterated that in a December report recounting
what happened.
One of the
first steps in making vaccines involves growing bacterial or viral
cultures. Certain animal-derived ingredients are added to help
the cultures grow; some, for instance, are briefly bathed in blood
from calves or sugars from cow's milk. The vaccine mix then undergoes
repeated purification.
The FDA warned
manufacturers starting in 1993 that as a precaution, they should
not use cattle-derived ingredients from any country infected with
mad cow disease, or bovine spongiform encephalopathy.
Companies
caught in violation said they had used the same ingredients for
decades and didn't realize FDA was concerned about culturing.
The FDA's
scientific advisers determined the risk theoretical, noting many
ingredients aren't made of BSE-infectious tissue, such as milk
sugars. Last month, the same advisory panel warned that some dietary
supplements--products containing raw cows' brains, the most infectious
tissue, and other animal organs--are of far more concern but are
not being properly checked by the FDA.
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