Development of Antiviral Drugs for Influenza.

The efficacy of the anti-influenza drugs was examined before and after the 2009 H1N1 pandemic. Anti-influenza drugs reduce the viral load, which leads to improvement of symptoms, a reduced illness period, suppression of complications, and protection from transmission. It is desirable to administer antiviral drugs within 48 hours of the onset of symptoms. The use of antiviral drugs is limited mainly to individuals who are hospitalized, those who have severe, complicated, or progressive illness, or those who are at high risk for influenza complications in Western countries. On the other hand, the rapid diagnosis of influenza and treatment with antiviral drugs have been effective in Japan, leading to the suppression of worsening symptoms. Baloxavir, the newest anti-influenza drug, and neuraminidase inhibitors are recommended for use in adult patients.