evidence: The legacy of victims of the 1918 flu The quest to understand the 1918 flu fueled many scientific advances, including the discovery of the influenza virus. However, the virus itself did not cause most of the deaths. Instead, a fraction of individuals infected by the virus were susceptible to pneumonia due to secondary infection by bacteria. In an era before antibiotics, pneumonia could be fatal. [...] This article was originally published on The Conversation.