Pandemic Influenza

An influenza (flu) pandemic is currently being predicted by experts at the World Health Organization. This website describes pandemic influenza, the risk of it occurring in Canada, what makes it different from the 'ordinary' influenza we get every winter, and what the province is doing to prepare for a possible influenza pandemic.

What is pandemic influenza?

Pandemic influenza is a type of influenza that occurs every few decades and that spreads rapidly to affect most countries and regions around the world.

Key Facts about Pandemic Influenza

Until the virus is identified it is not possible to make a vaccine.
Pandemic influenza will spread very rapidly because people will have no immunity.
Pandemic influenza is likely to be more severe than ordinary influenza.
Groups at particular risk won't be known until the disease starts to circulate—they may be different from those in ordinary influenza years.
Antivirals are being stockpiled but they have limitations—their effectiveness won't be known until the virus is circulating.

How does an influenza pandemic start?

Influenza viruses are constantly changing, producing new strains and varieties. Pandemics occur when a virus emerges that is so different from previously circulating strains that few, if any, people have any immunity to it. This allows it to spread widely and rapidly, affecting many hundreds of thousands of people. A new pandemic virus may be the result of an animal virus and a human virus mixing to produce a new strain. The animal virus usually comes from birds.

How likely is an influenza pandemic?

Three pandemics occurred in the last century. Scientists predict that another pandemic will happen, although they cannot say exactly when that will be.

The virus

Unlike the "ordinary" influenza that usually occurs every winter in Canada, pandemic influenza can occur at any time of year.
There is a difference between a pandemic and an epidemic. A pandemic affects a higher number of people and a much larger geographic region.
Pandemics of influenza have occurred occasionally for centuries—three times in the last hundred years—resulting in many thousands of deaths.
Experts predict another pandemic, but cannot say exactly when it will happen. When it does, it may come in two or more waves several months apart. Each wave may last two to three months.
Pandemic influenza is much more serious than ordinary influenza. As much as a quarter of the population may be affected—maybe more.
Pandemic influenza is likely to cause the same symptoms as an ordinary influenza, but the symptoms may be more severe because nobody will have any immunity or protection against that particular virus.
A serious pandemic is also likely to cause many deaths, disrupt the daily life of many people and cause intense pressure on health and other services.
Every pandemic is different. Until the virus starts circulating, it is impossible to predict its full effects.

Who's at risk?

Once an influenza pandemic starts, everybody will be at risk of getting pandemic influenza. Certain groups may be at greater risk than others. Until the virus starts circulating, we will not know for sure who they will be.