Risk From Deadly Flu Strain Is Called Low
By LAWRENCE K. ALTMAN and MARC SANTORA
Published: April 14, 2005
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Even as health officials scrambled yesterday to unravel the mystery of how a
deadly strain of influenza virus was sent to thousands of laboratories
around the world, they declared the risk that anyone would develop influenza
was very low.
In 1957, the strain, known as A(H2N2), caused an estimated one million to
four million deaths in a pandemic known as Asian flu, but it has not been
detected in this country since 1968.
Scientists have detected no infections from the recent samples of the
dangerous strain since the specimens were sent out beginning on Sept. 10,
said Dr. Julie L. Gerberding, the director of the Centers for Disease
Control and Prevention in Atlanta.
The samples were sent to laboratories that may handle the influenza virus as
part of a federally mandated program meant to ensure accuracy of testing.
Meridian Bioscience Inc., in Cincinnati, sent the samples to about 4,000
laboratories in 18 countries. Most of the laboratories were in the United
States. Meridian declined to answer questions and issued a statement saying
it had complied with "all applicable regulations."
The problem might have never been uncovered except for an error made in a
laboratory in Vancouver, British Columbia, in late February. As part of a
standard procedure, the Vancouver laboratory sent a specimen from a woman
for follow-up testing at the National Microbiology Laboratory of Canada in
Dr. Frank Plummer, the scientific director at the Winnipeg laboratory, said
team members soon discovered that they had something troubling on their
hands - a strain of influenza that had not been seen for decades.
"We found this out in the middle of the night on Good Friday," Dr. Plummer
said. "For several hours, we were very concerned."
Immediately, he said, investigators tracked down the woman to determine
whether she was in fact infected with the strain. They asked her about her
recent travels, contact with birds and when she first felt sick. They
determined quickly that her respiratory symptoms were not from influenza.
The origin of the 1957 strain remained mysterious. Dr. Plummer said his team
called the center in Atlanta on March 26. By April 8, Canadian
epidemiologists had traced the strain to the specimens sent out by the
College of American Pathologists in Northfield, Ill., which had ordered them
The medical detectives found that a technician in Vancouver had somehow
contaminated the woman's specimen while working under a protective fume hood
on both her specimen and the 1957 strain from Meridian, Dr. Plummer said.
The error alerted officials to the problem. Canadian officials are
monitoring all workers who had any recent contact with the 1957 strain in
the 20 Canadian laboratories to which it was sent. So far none have become
sick. All the Canadian labs are said to have destroyed the specimens
containing the 1957 strain.
Dr. Jared N. Schwartz, a microbiologist and official of the College of
American Pathologists, said his group asked Meridian to include a type A
influenza virus in the test kit, but did not specify which strain. When
Meridian checked a United States government manual, he said, its team found
that the A(H2N2) strain could be sent to laboratories as a biosafety Level 2
microbe, the second-lowest level of danger in a four-class rating.
But Meridian apparently did not know that the C.D.C. and the National
Institutes of Health have been discussing upgrading the classification of
the A(H2N2) strain to Level 3, as Canada and some other countries have done.
Dr. Schwartz said that Meridian "perhaps did not use good judgment" in
selecting the A(H2N2) strain, and should not have sent the strain to Canada
and other countries without checking further on its biosafety
Dr. Plummer agreed, saying, "Meridian made an error in choosing the A(H2N2)
virus to send out." The strain was listed as A(H3N2), a common strain, on
the permit forms for customs, Dr. Plummer said.
In the United States, where thousands of laboratories received the A(H2N2)
strain, Dr. Gerberding said she did not know how many had destroyed it.
"While the risk of the situation is very low, we are not taking any chances,
and we are doing everything we can to make sure that there is no threat to
human health," she said.
The disease control center does not have regulatory authority over
distribution of the A(H2N2) influenza virus because it is not classified as
a dangerous agent relevant to bioterrorism, Dr. Gerberding said. Her agency
is consulting a number of influenza and other experts about the situation,
Since the late 1970's, the government has required laboratories in the
United States to pass quality assurance tests to document that they can
identify what they say they can identify.
The testing programs must be administered by nonprofit organizations. The
largest and oldest to do such testing is the pathologists college, Dr.
But an additional 15 or so groups administer such programs, said Dr. Mark S.
Birenbaum, a microbiologist at the American Association of Bioanalysts. He
said his group also ordered samples from Meridian and distributed them to
380 laboratories. When they received the supply from Meridian, the samples
were labeled as containing influenza A without specifying the strain.
The bioanalyst group sent the specimens to private laboratories and
hospitals on March 1 purposely not specifying what virus they contained.
The laboratories received a kit containing a specimen of an influenza A
virus, two specimens containing no virus, a specimen with a virus that was
not influenza, and a specimen with influenza B. The laboratories perform
tests as they would on a patient and then submit the findings for grading.
On Monday, Dr. Birenbaum said that he received notice from Meridian near
midnight that something was wrong with the samples the company had sent. The
C.D.C. contacted his office on Tuesday morning. The public learned of the
incident on Tuesday night based on information from the World Health
Organization, a United Nations agency in Geneva.