Swine flu cases resistant to Tamiflu are becoming more common, say scientists

tetano · Mar 18, 2013

The data comes from Dr Aeron Hurt, of the World Health Organisation collaborating centre for reference and research on influenza in Melbourne. He and his colleagues have found that approximately 2% of H1N1pdm09/swine flu cases are resistant to Tamiflu. While that is not large, an increasing proportion of the patients have never been treated with the drug ? so they have contracted a form of flu that is already resistant to it.

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http://www.guardian.co.uk/world/2013/mar/18/swine-flu-resistant-tamiflu-scientists

JJackson · Mar 18, 2013

Re: Swine flu cases resistant to Tamiflu are becoming more common, say scientists

This is now being picked you by several MSM sites but there is little additional data beyond there now being a relatively fit wild type strain which has a 2% foothold in the general population who have had no Oseltamivir treatment.
Given the rapidity with which the previous seasonal, pre pandemic, H1N1 went from non-resistant to fully resistant this is a cause for some concern.
Does anyone know which sequence change is conferring the resistance and what level of resistance is being achieved?
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sharon sanders · Mar 19, 2013

Re: Swine flu cases resistant to Tamiflu are becoming more common, say scientists

hat tip NS1 from GeneWurx

GeneWurx Impressions on FluTrackers thread:
Swine flu cases resistant to Tamiflu are becoming more common, say scientists

The data on file at GISAID indicates 17 of 27 pH1N1 Neuraminidase segments from Newcastle, Australia in 2011 carry NA 275Y. That Neuraminidase polymorphism (NA H275Y) is considered the primary mechanism behind antiviral drug resistance in pH1N1 at this time. The NA 247N marker is recognised as an alternate / secondary effector, though no NA 247N instance occurs within the 2011 Newcastle sequences at GISAID.

The related 30 HA segments fall onto the most widespread pH1N1 clade, Clade2:188T, according to circulation sampling. CladeCrossing from Clade3:186P is demonstrated as a mixture on 2 of the sequences that were sampled near the end of the 2011 Southern Hemisphere season. At least 38% of the distinct HA polymorphisms (22 of 58) in this batch also appear on pH1N1 sequences that carry the alternate TamiFlu Resistance marker NA 247N.

Vibrant62 · Mar 19, 2013

Re: Swine flu cases resistant to Tamiflu are becoming more common, say scientists

A concern here is the potential for a reassortment event between H5N1 and a tamiflu resistant H1N1, where a swopping of the N1 gene (and potentially others) occurs.

The potential for such a reassortment within pigs is reasonably high; this host is readily infected with human pH1N1 and H5N1 infections in pigs have also been recorded (but only in some countries). This raises the spectre of generation of a tamiflu resistant H5N1 virus should tamiflu resistance in pH1N1 become widespread, as occurred in the older seasonal H1N1 variant.

See http://www.flutrackers.com/forum/showthread.php?t=187659&highlight=h5n1+seroprevalence+pigs

and

http://www.flutrackers.com/forum/showthread.php?t=144267&highlight=h5n1+seroprevalence+pigs

JJackson · Mar 19, 2013

Re: Swine flu cases resistant to Tamiflu are becoming more common, say scientists

NS1 thanks for the research and Sharon for the post and links.
Now we wait to see just how fit it is, which should become clear next Northern Hemisphere season. Oseltamivir may not have been all that effective but it is/was the only widely available and easy to take option - apart from the vaccine which is also not very reliable.

Swine flu cases resistant to Tamiflu are becoming more common, say scientists

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