http://news.yahoo.com/s/ap/20100322/ap_on_bi_ge/us_med_vaccine_warning
FDA suspends Glaxo rotavirus vaccine as precaution
Mon Mar 22,
By LAURAN NEERGAARD, AP Medical Writer Lauran Neergaard,
WASHINGTON – U.S. health officials told pediatricians Monday to
temporarily quit using one of two vaccines against a leading cause of
diarrhea in babies, after discovering that doses of GlaxoSmithKline's
Rotarix were contaminated with bits of an apparently benign pig virus.
Glaxo's vaccine has been used in millions of children worldwide,
including 1 million in the U.S., with no signs of safety problems — and
the pig virus isn't known to cause any kind of illness in people or
animals, said Dr. Margaret Hamburg, commissioner of the Food and Drug
Administration.
But vaccines are supposed to be sterile, and because there is a
competing vaccine against diarrhea-causing rotavirus that has tested
clean — Merck's RotaTeq — the FDA decided to err on the side of caution.
"We don't want to scare parents," Hamburg told reporters. "This was a
difficult decision for us to make because there is no evidence at this
time that there is a risk to patients who have received this vaccine,
and we know there are real benefits for children to be vaccinated
against rotavirus."
Rotavirus causes severe diarrhea and is a leading child killer in
developing countries. In the U.S., with better health care, about 55,000
children a year were hospitalized for rotavirus infections and several
dozen died each year before vaccination began — with Merck's vaccine in
2006 and Glaxo's in 2008.
Glaxo said Monday that regulators abroad have decided not to change how
Rotarix is used while scientists probe the relevance of the discovery.
A group of scientists testing a new way to detect viruses in a variety
of products stumbled onto fragments of genetic material — broken pieces
of DNA — from what's called porcine circovirus-1 in Rotarix and alerted
Glaxo, which confirmed the findings and in turn alerted FDA, Hamburg
said.
Rotarix, an oral vaccine, is made from a weakened strain of human
rotavirus that has to be grown inside living cells before being purified
into a vaccine dose. Glaxo uses a line of monkey kidney cells, or vero
cells. Hamburg said the pig virus DNA fragments have been found in
Glaxo's cell bank, meaning they were present from the vaccine's earliest
development. How the original contamination occurred is under
investigation.
Merck's competing rotavirus vaccine RotaTeq is made by a very different
process, and FDA's testing showed no sign of the pig virus in it.
It's not the first time unwanted viruses have been discovered in
vaccines. Best known is a monkey virus that contaminated some polio
vaccine in the 1950s; years later, scientists investigated if the SV40
virus might have increased vaccine recipients' risk of later-in-life
cancer but concluded it didn't.
"We live in a world that's teeming with microbes," Hamburg said, but
until now this particular pig virus is not one that FDA thought vaccine
makers needed to check their products against.
Parents should switch to the Merck vaccine for now — it requires three
doses instead of Glaxo's two — because rotavirus is too serious a
disease to ignore, said Dr. William Schaffner, a vaccine specialist at
Vanderbilt University who was briefed on FDA's decision.
He's bracing for calls from worried parents and will tell them that
"this has been an extraordinarily safe vaccine," and that the discovery
is "a consequence of our improved science and ability to detect things
that we never could before."
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Posted - 04/07/2010 :
18:10:29 
