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|Paradigm Shift Intervention Monitoring||Audio: Jan28 Apr21 Sep22
Tamiflu Resistance at 100% In Pennsylvania
The week 51 CDC report gives test results on 65 H1N1 isolates. 64 are H274Y positive. The only oseltamivir sensitive case was a clade IIC isolate that was included in the report on the first 2 H1N1 positives. Thus, all 63 tested since the first report have been H274Y positive. The results from Canada were similar. Although the National Labs in Winnipeg had only tested three H1N1 isolates, British Columbia reported results for 14 and all 17 Canadian H1N1 isolate were also positive. In Europe, all reported H1N1 results have been H274Y, except one early clade IIC isolate from England.
Sequences from the early isolates in the US have been released by the CDC, confirming that the one sensitive isolate was clade IIC and the remaining isolates were clade IIB and contained HA A193T. The same change was found in the dominant H1N1 in South Africa, signaling its role in widespread dominance of H1N1 with H274Y.
The US sequences were from isolates in Hawaii, Texas, Pennsylvania, and Wisconsin, further demonstrating that this A193T sub-clade is widespread. Some state agencies are still citing the low number of H1N1 isolates tested as a lack of evidence that near term H1N1 isolates will have H274Y. However, the sequence data , as well as frequencies in the US, Canada, and Europe suggest that H1N1 in these areas will have H274Y in NA and A193T in HA.
In countries where H1N1 is dominant, like the United States and Canada, advisories on oseltamivir usage will be issued.