Emergence of seasonal influenza viruses type A/H1N1 with oseltamivir resistance in some European Countries at the start of the 2007-8 influenza season
http://www.flutrackers.com/forum/showthread.php?t=51648
(The above raises a question and I have posted some preliminary thoughts below but would be interested in the thoughts of others.)
This is a predictable and not particularly surprising development. Resistance has been seen before in both seasonal flu and HP AI H5N1.
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The question which needs to be addressed – preferably collectively and under the guidance of the WHO – is what do we use Tamiflu for?
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Tamiflu was developed as a treatment for seasonal flu, with the threat of an HP AI zoonotic emergence it has become our only extant weapon against a far greater potential enemy: Pandemic HP H5N1. That there are several known mutations that reduce the effectiveness of Tamiflu is well know as is the fact that using any antiviral will give a selective advantage to those mutations, when they occur. The more Tamiflu continues to be used to treat seasonal flu the higher the proportion of the circulating virus that will show some resistance. How much this matters depends on how correct Dr. Niman is in his estimation of the importance of recombination as the primary means of flu’s evolution. If evolution is largely confined to Reassortment and random mutations then having resistance in the seasonal flu gene pool does not greatly increase the risk of resistance in a pandemic form. If however Recombination is common, and a pandemic form emerges without resistance, it is likely to quickly acquire it by swapping genetic material with seasonal flu in cases of dual infection and a pervasive Tamiflu blanket.
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So we return to the question of how do we use Tamiflu, do we try and restrict its use in seasonal flu cases – where we know it can do good – to preserve its usefulness to fight a pandemic which may not occur in the short term, may not be susceptible to Tamiflu and only really matters if recombination is a significant factor.
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Personally I would favour making all doctors aware of the dilemma and recommending extreme restraint in its use. Where resistant cases are know greater efforts should be employed in quarantining patients to reduce the prevalence of resistant strains.
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JJ
http://www.flutrackers.com/forum/showthread.php?t=51648
(The above raises a question and I have posted some preliminary thoughts below but would be interested in the thoughts of others.)
This is a predictable and not particularly surprising development. Resistance has been seen before in both seasonal flu and HP AI H5N1.
<?xml:namespace prefix = o ns = "urn:schemas-microsoft-com
fficeffice" /><o></o>The question which needs to be addressed – preferably collectively and under the guidance of the WHO – is what do we use Tamiflu for?
<o
></o>Tamiflu was developed as a treatment for seasonal flu, with the threat of an HP AI zoonotic emergence it has become our only extant weapon against a far greater potential enemy: Pandemic HP H5N1. That there are several known mutations that reduce the effectiveness of Tamiflu is well know as is the fact that using any antiviral will give a selective advantage to those mutations, when they occur. The more Tamiflu continues to be used to treat seasonal flu the higher the proportion of the circulating virus that will show some resistance. How much this matters depends on how correct Dr. Niman is in his estimation of the importance of recombination as the primary means of flu’s evolution. If evolution is largely confined to Reassortment and random mutations then having resistance in the seasonal flu gene pool does not greatly increase the risk of resistance in a pandemic form. If however Recombination is common, and a pandemic form emerges without resistance, it is likely to quickly acquire it by swapping genetic material with seasonal flu in cases of dual infection and a pervasive Tamiflu blanket.
<o
></o>So we return to the question of how do we use Tamiflu, do we try and restrict its use in seasonal flu cases – where we know it can do good – to preserve its usefulness to fight a pandemic which may not occur in the short term, may not be susceptible to Tamiflu and only really matters if recombination is a significant factor.
<o
></o>Personally I would favour making all doctors aware of the dilemma and recommending extreme restraint in its use. Where resistant cases are know greater efforts should be employed in quarantining patients to reduce the prevalence of resistant strains.
<o
></o>JJ
