WEDNESDAY, May 2 (HealthDay News) -- Data in a formerly banned
study detailing how the H5N1 avian (bird) flu virus can morph --
with the possibility that it could spread from person to person and
cause a global pandemic -- may help nations prepare for the
That's some of the motivation for lifting the ban and publishing
the study in the May 2 online issue of
Nature, experts say.
The initial ban applied to two studies slated to be published in
two medical journals,
Science. In December, the U.S. government intervened, requesting that both journals censor some of the data for national security purposes. The concern was that terrorists might use the information to create a lethal biological weapon.
The ban was lifted in April, after the U.S. government conducted
a risk assessment in March.
Nature also commissioned an independent assessment. Both
showed that publication would confer more public benefit than
Nature study, Yoshihiro Kawaoka, a professor of virology at
the University of Wisconsin-Madison, and colleagues tweaked the
H5N1 virus using genetic material borrowed from H1N1 'swine' flu to
see if it would transmit easily between ferrets -- an animal model
thought to be closely related to humans.
These genetic changes can make the virus easier to transmit, the
study found. Knowing their footprints can help researchers know
what to look out for and hopefully catch the virus early before it
begins to spread.
"H5N1 viruses remain a significant threat for humans as a potential pandemic flu strain," Kawaoka said. "We have found that relatively few mutations enable this virus to transmit in mammals."
The information provided by this study is important as the virus
could mutate on its own. Now "we can better prepare should a
pandemic virus emerge in nature," Kawaoka said. Currently available
vaccines and antivirals are effective treatments for this
"Stockpiling H5N1 vaccines and antivirals will be important for pandemic preparedness," he said, and flu trackers too can use this information when they develop vaccines in the future. "Just as for a seasonal flu vaccine, it will be important for an H5N1 vaccine to be made to a closely related virus, so knowing which mutations may confer transmissibility will help prioritize vaccine candidates," Kawaoka explained.
The new data also help advance science by increasing the
understanding of the basic biology of flu transmission. "Sharing
the data with other scientists will lead to important additional
discoveries that may aid the development of improved vaccines and
therapeutics," Kawaoka said.
There had been doubt that the bird flu could mutate and cause a
pandemic, said microbiologist Joseph Sriyal Malik Peiris, of the
University of Hong Kong. He was a co-author of a journal editorial
accompanying the new study. He said this research does suggest that
bird flu can mutate. "It suggests that the H5N1 virus can
potentially acquire transmissibility in humans. However, whether it
will ever do so is another matter."
While there have been sporadic cases of bird flu in humans,
these have been traced to people directly handling live birds, for
instance while working in a poultry market.
Importantly, this research and its publication are not a threat
to U.S. security, Peiris said. "This research only tells us that
the mutated H5N1 transmits in ferrets. It also tells us that the
mutated virus no longer kills ferrets," he said. "Why would anyone
who wanted to 'create harm' put so much effort into generation of
such a virus with so much uncertainty on how it would work in
But, Peiris noted, the study "is important for pandemic risk
assessment because it gives indications of the mutations that we
should be watching out for."
Dr. Bruce Hirsch, an infectious diseases specialist at North
Shore University Hospital in Manhasset, N.Y., agreed that
publication is likely to do more good than harm. "We should be
aware of the fact that this influenza can mutate," he said.
"Publication makes us safer because we know what to look out for
now. This can help facilitate preventive strategies and can
eventually lead to more effective vaccine development and antiviral
He added, "We live in a much smaller world because of air travel
and population density and certainly we are more vulnerable to
viruses as a result."
This virus is not likely to be used by terrorists to cause a
pandemic, Hirsch said. "It became less lethal in the animal model.
I am reassured by the fact that the ability to make it a 'terror'
virus has not really been demonstrated."
Learn more about
flu at the U.S. Centers for Disease Control and Prevention.
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