Influenza prevention, 1918 pandemic. News poster showing a nurse with a gauze mask (left). The text next to the image provides public health guidance on preventing infection by the influenza virus. Suggestions include covering the mouth when coughing and sneezing. The 1918 Spanish flu pandemic, which occurred in several waves between 1918 and 1920, infected one fifth of the world population and killed between 20 and 50 million. This poster, designed to be displayed in shop windows, was published on 18 October 1918 by 'Illustrated Current News', New Haven, Connecticut, USA. Photograph by Paul Thompson, New York, USA.