Antiviral agents for prevention and / or treatment of influenza virus infections : old and new : main topic

Yearly epidemics of influenza are a cause of considerable morbidity and mortality worldwide. Influenza vaccination is the primary means of prevention of infection and its complications. Antiviral agents are an adjunct to vaccination for control and prevention of influenza infection, but should never be used as a substitute for vaccination. Two classes of antiviral agents are available for the prevention and treatment of influenza infection, the adamantanes and the neuraminidase inhibitors. Adamantanes block the M2 protein channels of the influenza A virus and prevent uncoating of the virus inside the cells, so inhibiting replication. The neuraminidase inhibitors block the activity of viral neuraminidase, so preventing the release of newly formed viruses from cells. Amantadine, an adamantane available in South Africa, is 70 - 90% effective in preventing illness caused by influenza A infection, and when administered within 2 days of onset of illness can reduce the duration of uncomplicated influenza A infection.