Antiviral therapy in seasonal influenza and 2009 H1N1 pandemic influenza: Korean experiences and perspectives

Influenza is a major cause of substantial morbidity and mortality in humans every year. Vaccination is the main strategy to prevent influenza infection, but antiviral agents also play an important role in the control of both seasonal and pandemic influenza. During the influenza A/H1N1 pandemic in 2009, early prompt antiviral therapy may have reduced the severity of the influenza outcomes including pneumonia, hospitalization and mortality in the Republic of Korea. Since the 2009 H1N1 pandemic, there have been increasing usages of antiviral agents for the treatment of patients with seasonal influenza. Although currently rare, antiviral resistance among influenza viruses may emerge and increase with increased use of neuraminidase inhibitors. New agents with different modes of action are under investigation, including favipiravir, DAS181, nitazoxanide and broad-spectrum neutralizing monoclonal antibodies. Data are limited with respect to high-dose and combination antiviral therapies. So, clinical trials are warranted to evaluate diverse antiviral combinations that may be synergistic and less likely to induce breakthrough resistance.