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Resistance to influenza anitivirals is emerging. Many strains of influenza have already developed resistance to the older class of flu antivirals, the adamantanes. After four decades of effective use in the prophylaxis and treatment of influenza, global resistance to these drugs has increased dramatically among influenza viruses of the A/H3N2 subtype in recent years.1
The new class of influenza antivirals, neuraminidase inhibitors, oseltamivir (Tamiflu) and zanamivir (Relenza), are currently suitable for all strains. However, sporadic resistance has already been observed with oseltamivir, and we have no further line of defence currently. During the 2007-2008 influenza season, oseltamivir resistance among influenza A(H1N1) viruses increased significantly for the first time worldwide.2
During the 2009 flu pandemic, further reports of resistance occurred. If we encounter another flu emergency, or a highly pathogenic strain emerges, we rely on these drugs to help prevent spread and help reduce secondary complications and mortality.
- Nelson, M.I. et al. The origin and global emergence of adamantine resistant A/H3N2 influenza viruses. Virology 2009. 388,270-278
- Dharan, N.J. et al. Infections With Oseltamivir-Resistant Influenza A (H1N1) Virus in the United States. JAMA 2009. Vol. 301 No. 2