What is an influenza pandemic?
An influenza pandemic is a worldwide influenza epidemic that occurs when a completely new strain of influenza A virus infects the human population. Because people have little or no immunity to these new viruses, a high proportion of the population, perhaps 25 per cent or more over one to two years, may be infected and develop symptoms. Pandemic influenza strains are usually associated with higher rates of serious complications, including hospitalisation and death, than the normal seasonal influenza viruses that cause smaller epidemics each year during winter.
