Tamiflu Resistance in England Exactly Matches United States
Recombinomics Commentary 14:55
April 19, 2008
Two H1N1 NA sequences from England were just released at Genbank. One isolate, A/England/557/2007(H1N1), had the oseltamivir (Tamiflu) resistance marker, H274Y. The sequence exactly matched three sequences from the United States, A/Wisconsin/01/2008, A/New Jersey/20/2007, A/New Jersey/05/2008. The sample from England was collected November 15, 2007 which was two weeks prior to the 2007 match in New Jersey. The 2008 isolates in the US were collected near the end of January, 2008.
The identity between these four isolates, as well as the close relationship to other isolates in the US with H274Y signals evolutionary fitness for this isolate, and further decreases the likelihood that the acquisition of H274Y in these isolates is due to independent events.
The sudden increase in H274Y in H1N1 seasonal flu has startled influenza experts. In the UK and US, the resistance is in approximately 10% of the H1N1 samples, but is above 40% in samples from Norway, France, and Russia. The genetic change that generates H274Y in H1N1 seasonal flu matches the change in H5N1 pandemic flu, and follows the implementation of Tamiflu blankets to control H5N1 in southeast Asia and the Middle East.
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