Influenza: The 2009 H1N1 Pandemic And Antiviral Treatment Options

Purpose. To provide an overview of the 2009 H1N1 influenza pandemic and antiviral treatment options for influenza. Summary. Influenza infection causes significant morbidity and mortality every year. The high mutation rate and segmented nature of influenza virus genome gives rise to high genetic variability which enables the virus to escape antiviral and vaccine interventions. A novel H1N1 strain of influenza virus known as the swine-origin influenza virus has emerged and established itself recently in the population. The result has been the first influenza pandemic to develop in the 21st century. This new H1N1 virus is resistant to the M2 ion channel inhibitors (amantadine and rimantadine), one of the two classes of anti-influenza drugs. Neuraminidase (NA) inhibitors (oseltamivir and zanamivir) became the only treatment options for the novel H1N1 virus. NA inhibitors work by interfering with the cleavage of sialic acid and preventing the release of viruses, thereby preventing further infection. However, an oseltamivir-resistant H1N1 pandemic strain has been identified in patients. Thus, the emergence of antiviral resistance and the limited treatment options available highlight the urgent need for developing new antiviral agents to combat H1N1 infection. In response to this urgent call, the unapproved investigational drug intravenous peramivir was authorized by the FDA for emergency use. In addition, several new drugs for influenza treatment are currently under development. Conclusion. Understanding the origin, pathogenicity, resistance potentials of influenza viruses, and the availability of new treatment options is crucial for influenza pandemic preparedness.