Brief history and epidemiological features of pandemic influenza.

This chapter discusses pandemics that have occurred previously and introduces the concept of pandemic preparedness upon which subsequent chapters focus. Section headings are: prerequisites for pandemic influenza; pandemics before the 20th century; influenza pandemics of the 20th century; swine flu, 1976; re-emergence of influenza A/H1N1 in 1977; antigenic recycling in relation to human pandemics; and pandemic preparedness.