in the United States in 1976 with the outbreak of influenza which caused infection in 230 military personnel (with one fatal outcome) which was clearly derived from swine influenza virus. What are the geographic origins of pandemic influenza? The most recent pandemics are thought to have arisen in China which has become known as the "epicenter" for the origin of pandemic influenza viruses. Living conditions in China seem to make it particularly feasible for animal to human transmission of influenza virus. In the villages of rural China pigs are sometimes raised in the same living quarters as their owners. This close contact is thought to promote interspecies transmission of the virus. The 1957 epidemic (H2N2) became known as the "Asian Flu" pandemic. The 1968 (H3N2) pandemic became known as the "Hong Kong flu". Only the 1918 influenza pandemic which was caused by the H1N1 subtype is thought not to have arisen in China but in Europe and has become known as the legendary "Spanish Flu". Each of these pandemics has been characterized by a major shift in one or both of the hemagglutinin or neuraminidase subtypes. How can we (globally) best be prepared for an unpredictable influenza pandemic? The two primary goals of a global prevention program are to gain an understanding of the epidemiology of influenza and to promptly isolate influenza virus from new outbreaks and distribute them for vaccine production. Once a new variant is detected, large quantities of vaccine will have to be produced since this is