Influenza pandemic (H1N1) 2009 (44): receptor binding
Date: Thu 12 Sep 2009
Source: The Times onlline [edited]
<http://www.timesonline.co.uk/tol/news/uk/health/Swine_flu/article6828915.ece>
Scientists warn over swine flu virus potency
--------------------------------------------
Swine flu [influenza pandemic (H1N1) 2009 virus] can infect cells
deeper in the lungs than seasonal flu, making people who catch it
more likely to develop serious complications, research suggests.
The study published in the journal Nature Biotechnology provides the
1st laboratory corroboration of reports from front-line doctors.
Seasonal strains of flu attach themselves almost exclusively to cells
found in the nose, throat and upper airway, producing some of
influenza's signature symptoms: a runny nose, scratchy throat and a
dry cough. But the research shows that [influenza pandemic (H1N1)
2009 virus] -- by sticking to a greater range of receptors -- can
also reach cells deep in the lungs.
It comes as the [UK] Government's chief scientific adviser said today
[12 Sep 2009] that swine flu could reach a peak in the next month or
so. Professor John Beddington said that a 2nd wave of infections was
expected "not much before October at the earliest." Thereafter
research and epidemic-modelling suggested the virus would be
weakened, he said. "You can get infections coming back in a number of
waves but it is likely that the next one will be larger than any
subsequent ones," Professor Beddington told the British Science
Festival at the University of Surrey.
The Government revised its planning assumptions for the swine flu
pandemic last week, with 19 000 people in Britain expected to die in
the "worst-case scenario." A previous estimate put the figure at 65
000. However, it is still estimated that up to 30 percent of the
population will fall ill. While most will get better within a week or
so, some may develop secondary infections or pneumonia, which can be
fatal. At least 70 people in Britain have died after contracting
[influenza pandemic (H1N1) 2009 virus infection] and hundreds have
required hospital treatment.
In the latest research, Professor Ten Feizi and colleagues at
Imperial College London carried out laboratory experiments in which
86 different receptors were exposed to seasonal and pandemic flu. The
seasonal strains only locked onto the kind of receptors found in the
upper respiratory track. But the [influenza pandemic (H1N1) 2009
virus] was also able to latch onto receptors found inside the lungs,
although more weakly. The adhesion results in a more severe lung
infection. Professor Feizi said: "If the flu virus mutates in the
future, it may attach to receptors deep inside the lungs more
strongly, and this could mean that more people would experience
severe symptoms. We think scientists should be on the lookout for
these kinds of changes in the virus so we can try to find ways to
minimise the impact."
Some experts and critics of the Government have suggested that there
will not be enough NHS [National Health Service] intensive care beds
in the NHS to cope with the demand expected in a 2nd wave of the
pandemic. But how severe the outbreak is will depend largely on how
many people have already had the illness, Professor Beddington added.
It is difficult to estimate the number of unreported cases, he said.
Someone could just feel a bit sniffly and irritable but actually have
the virus. If this applies to a large fraction of the population then
the 2nd wave will be small.
So far about 450 000 doses of the drug Tamiflu (oseltamivir) have
been distributed, 10 times the number of confirmed flu cases.
Professor Beddington defended the decision to treat large numbers of
the population with antiviral drugs, but admitted that the official
Scientific Advisory Group for Emergencies (Sage) had been divided on
whether Tamiflu should be made universally available. Some members of
the group, which advises the Cabinet, had feared that providing
antivirals to everyone infected risked the virus developing
resistance, he said. But he added that there was little evidence that
the virus had built up any resistance.
[Byline: David Rose and Hannah Devlin]
Source: The Times onlline [edited]
<http://www.timesonline.co.uk/tol/news/uk/health/Swine_flu/article6828915.ece>
Scientists warn over swine flu virus potency
--------------------------------------------
Swine flu [influenza pandemic (H1N1) 2009 virus] can infect cells
deeper in the lungs than seasonal flu, making people who catch it
more likely to develop serious complications, research suggests.
The study published in the journal Nature Biotechnology provides the
1st laboratory corroboration of reports from front-line doctors.
Seasonal strains of flu attach themselves almost exclusively to cells
found in the nose, throat and upper airway, producing some of
influenza's signature symptoms: a runny nose, scratchy throat and a
dry cough. But the research shows that [influenza pandemic (H1N1)
2009 virus] -- by sticking to a greater range of receptors -- can
also reach cells deep in the lungs.
It comes as the [UK] Government's chief scientific adviser said today
[12 Sep 2009] that swine flu could reach a peak in the next month or
so. Professor John Beddington said that a 2nd wave of infections was
expected "not much before October at the earliest." Thereafter
research and epidemic-modelling suggested the virus would be
weakened, he said. "You can get infections coming back in a number of
waves but it is likely that the next one will be larger than any
subsequent ones," Professor Beddington told the British Science
Festival at the University of Surrey.
The Government revised its planning assumptions for the swine flu
pandemic last week, with 19 000 people in Britain expected to die in
the "worst-case scenario." A previous estimate put the figure at 65
000. However, it is still estimated that up to 30 percent of the
population will fall ill. While most will get better within a week or
so, some may develop secondary infections or pneumonia, which can be
fatal. At least 70 people in Britain have died after contracting
[influenza pandemic (H1N1) 2009 virus infection] and hundreds have
required hospital treatment.
In the latest research, Professor Ten Feizi and colleagues at
Imperial College London carried out laboratory experiments in which
86 different receptors were exposed to seasonal and pandemic flu. The
seasonal strains only locked onto the kind of receptors found in the
upper respiratory track. But the [influenza pandemic (H1N1) 2009
virus] was also able to latch onto receptors found inside the lungs,
although more weakly. The adhesion results in a more severe lung
infection. Professor Feizi said: "If the flu virus mutates in the
future, it may attach to receptors deep inside the lungs more
strongly, and this could mean that more people would experience
severe symptoms. We think scientists should be on the lookout for
these kinds of changes in the virus so we can try to find ways to
minimise the impact."
Some experts and critics of the Government have suggested that there
will not be enough NHS [National Health Service] intensive care beds
in the NHS to cope with the demand expected in a 2nd wave of the
pandemic. But how severe the outbreak is will depend largely on how
many people have already had the illness, Professor Beddington added.
It is difficult to estimate the number of unreported cases, he said.
Someone could just feel a bit sniffly and irritable but actually have
the virus. If this applies to a large fraction of the population then
the 2nd wave will be small.
So far about 450 000 doses of the drug Tamiflu (oseltamivir) have
been distributed, 10 times the number of confirmed flu cases.
Professor Beddington defended the decision to treat large numbers of
the population with antiviral drugs, but admitted that the official
Scientific Advisory Group for Emergencies (Sage) had been divided on
whether Tamiflu should be made universally available. Some members of
the group, which advises the Cabinet, had feared that providing
antivirals to everyone infected risked the virus developing
resistance, he said. But he added that there was little evidence that
the virus had built up any resistance.
[Byline: David Rose and Hannah Devlin]
Posts
No comments:
Post a Comment