FDA issues warning about diarrhea vaccine Rotarix

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FDA issues warning about diarrhea vaccine Rotarix

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The Associated Press

Date: Monday Mar. 22, 2010 3:15 PM ET

WASHINGTON — U.S. health officials urged pediatricians Monday to temporarily

stop using one of two vaccines against a leading cause of diarrhea in

babies, after discovering that doses of GlaxoKline's Rotarix were

contaminated with bits of an apparently benign pig virus.

British-based GSK's vaccine has been used in millions of children worldwide,

including one 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 GSK's in

2008.

GSK said Monday that regulators abroad have decided not to change how

Rotarix is used while scientists probe the relevance of the discovery.

Regulators from the U.S., Canada and the European Union and the World Health

Agency were to meet to discuss the issue Tuesday and Wednesday of this week.

While Canada hasn't told doctors to stop using the GSK vaccine, there is

currently no need. There are no doses of Rotarix available in Canada, Health

Canada spokesperson Stephane Shank said in an email.

Trembinski, a GSK Canada spokesperson, said " limited quantities " of

the vaccine were sold in Canada in 2009, but Rotarix is currently out of

stock in Canada. She did not say why the company hadn't been pushing the

vaccine in the Canadian market.

But a spokesperson for Merck Frosst, which sells RotaTeq in Canada, said

most Canadian children who have been immunized against rotavirus have

received the Merck vaccine.

" The vast majority of . . . Canadian children have been vaccinated against

rotavirus gastroenteritis have been vaccinated with RotaTeq, which is the

Merck vaccine, " Sheila said from Montreal.

" And there is no issue with RotaTeq. It's been examined by the same

researchers that found this problem with Rotarix. "

The problem came to light when 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 GSK, 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. GSK uses a line of monkey kidney cells, or vero cells. Hamburg

said the pig virus DNA fragments have been found in GSK's cell bank, meaning

they were present from the vaccine's earliest development. How the original

contamination occurred is under investigation.

Merck's RotaTeq is made by a very different process, and FDA's testing

showed no sign of the pig virus in it.

It is 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 GSK's two -- because rotavirus is too serious a disease to

ignore, said Dr. Schaffner, a vaccine specialist at Vanderbilt

University who was briefed on FDA's decision.

He is 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. "

With files from The Canadian Press

http://www.ctv.ca/servlet/ArticleNews/story/CTVNews/20100322/FDA_vaccine_100322/\

20100322?hub=Health