Tamiflu Resistance Explodes in Chicago
Recombinomics Commentary 18:59
February 16, 2008
Authorities say eight of the ten Tamiflu-resistant infections came from an outbreak at a single Chicago health care facility
The above comments on ten oseltamivir resistant cases in Chicago, including eight from one health care facility, suggest the incidence of Tamiflu resistance is on the rise in the United States. To date the US has reported 16 cases for the entire season, so if the 10 cited above are in the infleunza surveillance network, the number of positives will be markedly higher in the near term. It is likely that the 10 will be H1N1 and resistant because of H274Y, which is true for all isolates reported this season in the United States.
The high concentration at one facility suggests the H274Y is evolutionarily fit, although there is a possibility that these patients were being treated with Tamiflu. However, reports from Europe, where Tamiflu resistance is high, indicate such cases were not treated with Tamiflu.
These cases could pose a serious health problem in at risk populations because Tamiflu is rendered useless by H274Y, and the recent H1N1 isolates in the US and Europe have been the Brisbane strain, which is not well recognized by the current trivalent vaccine. The match failures for H3N2 and influenza B, coupled with the poor match for Brisbane H1N1 has been associated with rapid spread of influenza in the United States, which has generated an MMWR report this week, and the second CDC news conference in a week.
This latest explosion in Tamiflu resistance suggests the frequency will continue to grow. The Tamiflu status of these 10 patients would be useful.
Media Links
Recombinomics Presentations
Recombinomics Publications
Recombinomics Paper at Nature Precedings