33a20394_Immunise___Glossary_P_Q_R_S_Definition
[Term] Pandemic, pandemic influenza [Definition] 
A pandemic epidemic occurs over a very wide area, crossing international boundaries and usually affects a large number of people. For example, pandemic influenza is when there is a global epidemic of influenza that results when a new strain of influenza (flu) virus appears in the human population. It may cause more severe disease in the population due to little immunity to the new strain.
Immunise - Glossary
Definition