In anticipation of biological warfare, military personnel were given the anthrax vaccine during the 1990s Gulf War. After their service, Gulf War veterans suffered a wide range of debilitating symptoms that became known as the Gulf War illness or "Gulf War Syndrome."

Many vaccines have heterogeneous effects across individuals. Additionally, some vaccines do not prevent infection, but reduce disease-associated mortality and transmission. Both of these factors will alter selection pressures on pathogens and thus shape the evolution of pathogen virulence. We use a ...