| Concerns Grow Over Possible
H1N1-H5N1 Reassortment
Virologists and influenza authorities are becoming increasingly
concerned that the 2009 A-H1N1 flu virus could “reassort”
with the highly virulent H5N1 avian flu that’s still prevalent
in parts of the world like China, and that a mutation could occur
resulting in a new strain that has the lethality of H5N1 and the
human transmissibility of A-H1N1.
The concerns have grown in the wake of revelations that mutations
of the H1N1 flu virus had been found in Norway and elsewhere,
leading experts to fear that it might just be a matter of time
before there’s a reassortment of H1N1 and H5N1.
This comes as the World Health Organization (WHO) reported very
high pandemic activity in Italy, Norway, the Republic of Moldova,
the Russian Federation (Urals region), and Sweden.
Bulgaria, Denmark, Finland, Germany, Iceland, Ireland, Lithuania,
Luxembourg, Poland, Portugal, the Russian Federation, Serbia,
Turkey, and Ukraine also reported high pandemic activity.
Meanwhile, authorities said they believe the peak of the A-H1N1
pandemic's second wave hasn’t yet been reached in some parts
of the world.
WHO said it’s keeping a "very careful” eye on
the reported mutations in order to ascertain whether it is causing
more severe illness diseases than the A-H1N1 virus.
"We really need to look at this very carefully to see whether
it is in fact associated with severe cases," WHO spokesman
Thomas Abraham told reporters. He said investigations by WHO's
collaborating network of labs will be able to provide a better
"understanding … about clinical features associated
with the infection of this particular form of the virus."
Since it emerged, the A-H1N1 virus has constantly been mutating,
authorities said. So far, most of these mutations have no clinical
significance, but "occasionally we come across a virus that
might have clinical significance,” Abraham said.
WHO warned that the H5N1 virus has emerged in poultry in Egypt,
Indonesia, Thailand and Vietnam just as the H1N1 pandemic influenza
continues its rampage across the world.
Not only does this place “those in direct contact with birds
- usually rural folk and farm workers - at risk of catching the
often-fatal disease,” but “the virus could undergo a
process of ‘reassortment’ with another influenza virus
and produce a completely new strain," WHO stated.
"The most obvious risk is of H5N1 combining with the pandemic
... [H1N1] virus, producing a flu virus that is as deadly as the
former and as contagious as the latter."
That the two flu strain could merge, reassert, and produce a
new hybrid influenza strain combining the worst elements of each
of the viruses is a possibility that authorities have been worrying
about ever since the spread of the A-H1N1 virus increased to pandemic
level.
“We don’t know if this is possible, but we are certainly
aware of the risk,” Dr. Shin Young-soo, WHO Regional Director
for the Western Pacific,” told The Philippine Star. “We
are on alert for this development.”
“Influenza viruses are unpredictable. In areas where [A-H1N1]
is endemic, we and our partners and national governments are working
to build surveillance systems to identify changes in the behavior
of the virus,” Shin said. “We are also focusing on early-response
capacity to reduce the potential threats to human health.”
Virologists told HSToday.us that “it’s very possible
that the two flu strains could combine – this reassortment
that we talk about – that could result in a mix of the two,”
as one explained. “Of course, what we are concerned about
is a mutation that contains the worst characteristics of the two
viruses.”
Zhong Nanshan, director of the Guangzhou Institute of Respiratory
Diseases in China's southern Guangdong province, warned that China
has to be on high alert to any mutation and changes in the virulence
of A-H1N1.
"This is something we need to monitor, the change, the mutation
of the virus. This is why reporting of the death rate must be
really transparent,” he told Reuters Television, adding,
China, as you know, is different from other countries. Inside
China, H5N1 has been existing for some time, so if there is really
a reassortment between H1N1 and H5N1, it will be a disaster.”
WHO reported more than half-a-million laboratory confirmed cases
of H1N1 worldwide in mid-November and close to 7,000 deaths, but
stressed that in reality that figure is likely much, much higher.
Across Europe, the number of deaths related to pandemic H1N1
has doubled nearly every two weeks since mid-October.
US influenza and public health authorities agreed in interviews
with HSToday.us. They said the number of people infected in the
US is undoubtedly “much higher” than the number of lab-confirmed
cases given that most people who exhibit traditional H1N1 sickness
symptoms are not tested to determine if they have H1N1 or a seasonal
flu virus strain.
HSToday.us reported last week that four patients at Duke University
Medical Center in Durham, NC, at least five persons in a hospital
in Wales, and a father in Quebec, Canada become infected with
an apparently mutated strain of H1N1 that is resistant to Tamiflu
(oseltamivir), the leading antiviral of choice to treat influenza
in lieu of having a vaccine.
Meanwhile, Norwegian health authorities reported a potentially
significant mutation in H1N1 that could be responsible for the
severest symptoms in those infected by the strain - especially
persons most at risk to the virus.
Authorities have been monitoring this development very carefully
because of concerns that it, too, might become resistant to Tamiflu,
and, possibly, other antivirals if they become as widely administered
as oseltamivir.
Similar mutations have been reported elsewhere, but haven’t
necessarily provoked a more virulent virus or proven to be less
resistant to Tamiflu or other antivirals. Nevertheless, authorities
increasingly are concerned.
Virologists have been worried for some time that antiviral-resistant
influenza could become a serious problem during a pandemic, as
antivirals are the primary defense against a pandemic until an
effective vaccine is developed and distributed.
Additionally, the Centers for Disease Control and Prevention
(CDC) reported during a November 25 press briefing that there's
been "a worrisome spike in serious pneumococcal disease"
linked to A-H1N1 had appeared in the CDC's Active Bacterial Core
surveillance program that monitors infections at ten locations
across the nation.
CDC reported a tripling of cases of severe, life-threatening
bacterial infections at the monitoring sites.
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A full list of h1n1 vaccine ingredients, alerts and warnings.
Reference Sources: hstoday.us
December 3, 2009
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