Friday, January 16, 2009

Recombinomics: H1N1 Tamiflu Resistance Spreads Across Europe

[As Dr. Niman notes, and we note here: http://pandemicinformationnews.blogspot.com/2009/01/seasonal-flu-4-articles.html, H3N2 is dominant in Europe this season]

Commentary

H1N1 Tamiflu Resistance Spreads Across Europe
Recombinomics Commentary 16:54
January 16, 2009

More countries have reported on antiviral susceptibility based on genotyping (Norway, Spain, Sweden), phenotyping (Italy) or both techniques (UK).

Fifty-one of 52 influenza A(H1N1) viruses analysed (98%) were resistant to oseltamivir

The above comments from the week 2 EISS report indicates H1N1 Tamiflu resistance is spreading across Europe. Although H3N2 is the dominant influenza A serotype in Europe, H1N1 is widespread and at or near 100% Tamiflu resistant.

The UK week 2 report indicted 39/40 H1N1 isolates had H274Y. Thus, at least 12 H1N1 isolates in the EISS report are in countries outside of the UK, and all such isolates are resistant. The above list includes Spain and Italy as countries testing for antiviral resistance, so if the testing included H1N1, resistance would have been confirmed in those countries.

It is likely that all or most H1N1 in Europe will be resistant because the only sensitive isolate in the UK was among the first 10 tested, so all of the most recent 30 isolates in the UK are resistant. Similarly, all 23 of H1N1 isolates tested in Canada are also resistant, and the level is close to 100% in the United States, South Korea, and Japan.

Therefore, because all of the northern hemisphere countries have reported levels close to 100%, it is likely that other countries in Europe reporting H1N1 also have resistance. In the latest FluNet update, H1N1 has been confirmed in Belgium, Bulgaria, Denmark, Estonia, Germany, Greece, Portugal, Russia, and Slovenia. Therefore it is likely that H274Y is present in all of these countries as well as other countries in Europe who have not submitted serotype data.
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