The Origins of Pandemic Influenza — Lessons from the 1918 Virus.

The article focuses on the author's views on the origins of pandemic influenza. He discusses the three pandemic viruses that originated in the 20th century, namely the 1981 Spanish influenza H1NI virus, the 1957 Avian influenza H2N2 virus, and the 1968 Hong Kong influenza H3N2 virus. He reports that 1957 and 1968 witnessed the emergence of a new influenza virus due to reassortment events involving two influenza viruses containing the gene for one of the polymerase proteins from the avian virus.