Recombinomics: H1N1 Tamiflu Resistance Spreads Across Japan

Commentary

H1N1 Tamiflu Resistance Spreads Across Japan
Recombinomics Commentary 12:30
January 17, 2009

In the survey, local public health institute data was compiled by the National Institute of Infectious Diseases, which operates under the ministry. Data showed that 303 of the 671 influenza patients had the Hong Kong-A strain, and 243, or about 36 percent, had the Soviet-A strain. The other 125 had B-type influenza.

The Institute separately examined samples of the Soviet-A strain taken from 35 patients in 11 prefectures, and found that Tamiflu was ineffective for 34 of the patients, or 97 percent.

The above comments provide an update on oseltamivir resistance in Japan. The “Soviet-A” strain is H1N1 clade 2B Brisbane/59, which was phylogenetically described for three isolates from an elementary school outbreak in Sendai. Those sequences matched sequences in the United States from HI, TX, PA. An earlier WHO report indicated 13/14 H1N1 isolates had H274Y. the above report extends the resistance to 34/35 isolates collected from 11 prefectures, indicating the resistance is widespread.

The results from Japan match those of Korea. Where H1N1 cases have exploded and 16/17 H1N1 isolates had H274Y. Similar results have been described for the United States and Canada in North America, as well as England and many countries in Europe.

Since the H1N1 with H274Y in Japan is called the “Soviet –A” strain, it is likely that resistance levels in Russia and China are similar to Europe, North America, and Korea/Japan.

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