The Swine Flu Episode and the Fog of Epidemics1

The 1918 influenza pandemic has shaped research and public health for nearly a century. In 1976, the specter of 1918 loomed large when a pandemic threatened the country again. Public health officials initiated a mass vaccination campaign, but the anticipated pandemic failed to occur. An examination of the available data in 1976 and the decision to vaccinate, as well as lessons learned from the HIV/AIDS epidemic in the early 1980s, may help shape an appropriate public health response to future threats from avian influenza or other infectious diseases.