Perhaps the most promising route to heading off a pandemic influenza disaster is to try and minimise the chance of highly-virulent novel strains of the virus entering the human population in the first place. We now know that most virulent ‘flu strains jump into the human population from bird or pig reservoirs, and that ‘recombinant’ strains which contain novel mixtures of viral genes are particularly dangerous. Thus, reducing the number of situations in which humans, pigs and birds - particularly domestic poultry - live at high density in close proximity to one another is one way to delay, if not prevent entirely, the evolution of new influenza strains. However, in a world with two billion pigs, seven billion humans and 20 billion chickens, this is certainly easier said than done. In the meantime, avoiding a 21st century ‘Spanish ‘flu’ pandemic is probably going to rely on sensible tissue use, good hand washing - and a substantial amount of luck.