Illinois Issues Health Alert Due To Tamiflu Resistance
Recombinomics Commentary 20:25
February 16, 2008
Ten Chicago-area patients have tested positive for an unusual type of drug-resistant influenza, prompting concern and increased surveillance by local and federal health officials.
The Illinois Department of Public Health issued a health alert to doctors and hospitals Thursday, suggesting that flu patients who are in intensive care receive a combination of drugs until their virus can be analyzed.
"If you had two viruses in the same cell, they could recombine and generate a new virus," said Dr. Steven Wolinsky, chief of infectious diseases at Northwestern University. "The fact that we're seeing resistance to first-line medications is worrisome."
Bresee said no one can gauge how bad things are until more time has passed.
The above comments describe the Illinois health alert issued due to the oseltamivir (Tamiflu) resistance reported in Chicago. The comments also describe concerns that this resistance could spread. Since this change is almost certainly H274Y in H1N1, the spread could move toward H5N1, since the identical change has been reported in the avian N1. Moreover, the sudden appearance of H274Y in H1N1 may in fact be linked to the increased use of Tamiflu blankets to treat H5N1 outbreaks.
The totality of the match failures in this season’s trivalent vaccine highlights an increase in influenza genetic diversity, which is being reported in seasonal and pandemic influenza. In seasonal flu, the current vaccine for the northern hemisphere is 0 for 3. The Solomon Island strain for H1N1 is the closest match, but recent H1N1 outbreaks involve the Brisbane/59 strain, which reacts poorly with the current vaccine. Moreover, recent H274Y isolates are in the Brisbane/59 strain in the US and Europe.
Similarly, H5N1 is rapidly evolving. Clade 2.2 (Qinghai strain) which spread across Europe, the Middle East, and Africa is becoming increasingly complex and swapping polymorphisms to create new genes via recombination. This swapping may have generated the sudden appearance of H274Y worldwide in H1N1 isolates that are poorly recognized by the current vaccine.
The combination of a poor vaccine match and oseltamivir resistance could pose serious health risks for vulnerable populations, which may be the case in the Chicago health care facility with eight confirmed cases of Tamiflu resistance.
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