Ordinary vs. Pandemic Influenza

Some of the differences between pandemic and ordinary influenza are listed in the following table.

What is the difference between pandemic influenza and ordinary influenza?

ORDINARY INFLUENZA	PANDEMIC INFLUENZA
Occurs every year during the winter	Occurs about three times each century—at any time of the year
Affects up to 10 per cent of the population	May affect 15 to 35 per cent of the population
For most people, it is an unpleasant but not life-threatening infection, but can be life threatening for those with high-risk conditions.	It is a more serious infection for everyone.
The very young, the very old and people with certain chronic illnesses are most at risk of serious illness.	People of every age may be at risk of serious illness.
Annual immunization is available for those at risk of serious illness.	A vaccine won't be available at the beginning of a pandemic. When it does become available, the aim will be to immunize the whole population as rapidly as possible as soon as vaccine supplies become available.
Antiviral drugs are available to treat those at special risk.	Antiviral drugs are likely to be in limited supply and will have to be used for key groups of people: for example, treatment of individuals ill with influenza, health-care workers, and essential care workers required to care for the sick and keep the province running.