Health & Safety
16 January 2010
A flu pandemic is an epidemic of the flu virus that spreads on a worldwide scale and infects a large proportion of the human population.
Pandemic influenza is different from "ordinary" seasonal flu, which for most people is an unpleasant illness but runs its natural course (sometimes referred to as "self-limiting") and is not life endangering.
Pandemic flu can occur when a new influenza virus emerges that is markedly different from recently circulating strains and to which humans have little or no immunity.
Because of this lack of immunity, the virus is able to:
- infect more humans over a large geographical area,
- spread rapidly and efficiently from person to person,
- cause clinical illness in a proportion of those infected.