Oseltamivir-Resistant Influenza Viruses A (H1N1) in Japan (2007–2009)
Author Information
Author(s): Ujike Makoto, Shimabukuro Kozue, Mochizuki Kiku, Obuchi Masatsugu, Kageyama Tsutomu, Shirakura Masayuki, Kishida Noriko, Yamashita Kazuyo, Horikawa Hiroshi, Kato Yumiko, Fujita Nobuyuki, Tashiro Masato, Odagiri Takato
Primary Institution: National Institute of Infectious Diseases, Tokyo, Japan
Hypothesis
To monitor oseltamivir-resistant influenza viruses A (H1N1) in Japan during two influenza seasons.
Conclusion
The prevalence of oseltamivir-resistant influenza viruses A (H1N1) increased dramatically in Japan from 2.6% in the 2007–08 season to 99.7% in the 2008–09 season.
Supporting Evidence
- The total frequency of oseltamivir-resistant viruses was 2.6% during the 2007–08 season.
- During the 2008–09 season, 99.7% of the tested viruses were found to be resistant.
- Almost all oseltamivir-resistant viruses remained sensitive to zanamivir and amantadine.
- The current vaccine was effective against recent oseltamivir-resistant viruses.
- Continuous surveillance of these viruses is necessary due to their rapid increase.
Takeaway
This study found that a lot of flu viruses in Japan became resistant to a common medicine called oseltamivir, especially during the 2008-09 flu season.
Methodology
Analyzed clinical samples by NA sequencing and/or NA inhibition assay.
Limitations
The study primarily focused on two influenza seasons and may not represent long-term trends.
Participant Demographics
Clinical samples were collected from all 47 prefectures in Japan.
Digital Object Identifier (DOI)
Want to read the original?
Access the complete publication on the publisher's website