Pensito Flu Update: Tamiflu Resistance
From ProMed:
With the recent explosion of A(H1N1/2009) cases in Japan, it will probably be prudent to monitor for Tamiflu (oseltamivir) resistance. One Roche representative in Hong Kong told me that Japan accounts for about 70 percent of the world’s use of Tamiflu (even before avian H5N1 and the new H1N1/2009 viruses appeared). Thus, if Tamiflu resistance occurs with this new A(H1N1/2009) virus anywhere, it may well first happen in Japan. Also, a language barrier may delay this revelation.
However, now Tamiflu is used in many countries (particularly in Europe) in patients for whom it was previously not recommended (i.e., otherwise healthy adults with no underlying chronic disease or immuno-suppression with uncomplicated infection with seasonal influenza virus) to try to curtail the onward transmission of this new A(H1N1/2009) virus.
So, if this continues, ironically, maybe the rest of the world will catch up with Japan as a potential source of Tamiflu resistance. This policy may be counter-productive in that if this fails to control the spread of this virus, then in those who eventually need Tamiflu for serious illness (if the feared more lethal second wave of the pandemic does actually appear), it may be ineffective.
– —
Dr. Julian W Tang
Consultant Virologist
Division of Microbiology/Molecular Diagnostic Centre
Department of Laboratory Medicine
National University Hospital
[Dr. Tang identifies an important issue, namely whereas the widespread use of Tamiflu with the aim of disrupting the transmission of the novel strain of H1N1 influenza virus is fully justified, indiscriminate use of Tamiflu in non-urgent situations may hasten the evolution of Tamiflu-resistant strains. Many, but not all, healthcare agencies are aware of this possibility. Fortunately, in the case of seasonal influenza strains, Tamiflu-resistance has not always been accompanied by cross-resistance to the other currently available neuraminidase inhibitor, Relenza. — Moderator CP]
Singapore


