The period beginning in 2004 saw an extraordinary spurt in attention paid to avian and pandemic influenza in the United States and at the global level. A disease that for decades had languished in the ‘dull but worthy’ category of infectious diseases was elevated to a risk to global health security. The securitisation of influenza was not unproblematic. The influenza pandemic of 2009 turned out to be far milder than anticipated, and much of the scientific basis on which planning had proceeded and resources had been mobilised turned out to be wrong. Developing countries with other disease priorities were urged to pour resources into pandemic planning exercises and change poultry-raising practices. The article argues that for an issue to be securitised as a global health threat, it is essential that the United States takes the lead role (or at the very least supports efforts by other leading powers). It uses the Copenhagen School's analysis to examine how avian and pandemic influenza was securitised in the United States, and then uses the concept of framing to examine why this disease was securitised by looking at the prior existence of an issue culture or discourse around emerging infectious diseases, which gained salience after the 2011 anthrax attacks. It finally looks at the impact of securitisation on countries with different priorities.