Experts debate whether looming pandemic can
be averted with quick action
08:49 PM EST Jan 24
HELEN BRANSWELL
ANN ARBOR, Mich. (CP) - With a rising death toll in Vietnam and near daily
warnings that an influenza pandemic is imminent, some flu experts are giving
voice to an idea that would once have been unthinkable.
Could a flu pandemic be stalled or possibly averted with swift
and decisive action? Could a stockpile of anti-viral drugs donated to and
deployed in Southeast Asian countries experiencing avian flu outbreaks be used
as fire blankets to extinguish a pandemic strain in the earliest stages of its
human-to-human spread?
U.S. flu expert Dr. Arnold Monto raised the idea in a commentary
the New England Journal of Medicine released Monday to coincide with a symposium
on pandemic influenza organized by the University of Michigan school of public
health, where Monto teaches.
Other experts attending the conference said such a plan, while difficult to
implement, is worth exploring.
"It is certainly something that should be tried," said Dr. Malik Peiris, a
renowned flu expert from the University of Hong Kong.
"What we are seeing are occasional clusters at this point in time. You might
see bigger clusters. And if you are ready to go in effectively and intervene,
you might be able to control the virus before it becomes pandemic."
Large amounts of oseltamivir - sold under the brand name Tamiflu - would have
to be sent to Southeast Asia, where widespread outbreaks of the virulent H5N1
avian influenza strain has been ravaging poultry stocks for much of the past
year.
The strain has occasionally jumped to humans, generally with fatal results.
In the past year 52 people in Vietnam and Thailand are known to have become
infected and 39 of them have died.
Though there have been suspected cases of limited person-to-person spread -
including a family cluster from Thailand reported on in the journal Monday -
there has been no evidence of the sustained and efficient transmission that
would be needed for a pandemic to occur.
The idea Monto and others are promoting is that when cases of human-to-human
transmission are identified, contacts of those cases be put on anti-viral drugs
in a bid to prevent them from becoming ill - in effect creating a ring of
containment around each case.
The head of the World Health Organization's global influenza program said the
idea is worth a shot.
"Though it is an attractive option, no attempt has ever been made to
interrupt the transmission of an influenza virus; the results of such an
enormous and costly undertaking remain uncertain," Dr. Klaus Stohr acknowledged
in an editorial for the journal.
"The option deserves further investigation, however, particularly when viewed
against the profound effect a delay in global spread and a flattening of the
peak in disease prevalence could have during the initial phase of a pandemic."
Developed countries like the United States and Canada would have to pick up
the tab for the special stockpile, Monto said.
"It may be in the interest of developed countries to forestall the appearance
of a pandemic, even to delay the emergence out of the particular country of the
pandemic virus, so that they can better prepare themselves," he said in an
interview.
"It may be for selfish reasons . . . which are the most persuasive that
countries may decide to gamble with a bit of their own national stockpiles. I
think that it is critical, though, for this to be a global response."
But a leading U.S. epidemiologist suggested the idea was unworkable. Dr.
Michael Osterholm said there are neither enough anti-viral drugs available
globally nor a way to quickly find all possible cases of human-to-human
transmission and get drugs to their close contacts - and there isn't time to
find solutions to those problems.
"We can theoretically suggest a lot of possible interventions (but) we've got
to get real and start determining based on practical experience what is even
physically or scientifically possible," Osterholm, director of the Center for
Infectious Disease Research and Policy, said in an interview. Osterholm did not
attend the meeting.
Others, including Monto, acknowledged there would be "formidable" logistical
issues to be solved, but still maintained the idea is worth exploring.
The study on the probable cases of human-to-human transmission in Thailand
illustrate just how formidable the task might be.
In the paper, researchers from the Thai Ministry of Public Health and the
U.S. Centers for Disease Control, concluded a family cluster of H5N1 cases in
Thailand in September was probably the result of limited person-to-person
transmission.
It cannot be proven, but close study of the activities of the cases all but
confirms that a young girl was the source of infection for her mother and her
aunt, both of whom cared for her in hospital. The girl and her mother died; the
aunt survived. There was no evidence of further spread.
But the paper noted that the family cluster was caught after the fact by
chance, while authorities were investigating another pneumonia-related case.
Neither the girl nor the mother were recognized as H5N1 cases before their
deaths.
A more recent example occurred in Vietnam, where authorities have belatedly
confirmed a cluster of cases involving three brothers, one of whom died on Jan.
10.
For anti-virals to work as a prophylaxis - to stop disease - they must be
taken quickly after exposure. But as these examples underscore, detecting cases
early enough to be able to respond within the window of opportunity would not be
easy.
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