Pandemic Flu

Pandemic flu can result in something more than just a few days huddled up on the couch. It usually causes serious illness and by definition is a global event.

Pandemics are caused by newly emergent strains of the influenza virus. Sometimes they are the product of two strains that combine to form a 'super strain'. In these cases, the change in form that the virus undergoes is more radical than the small changes seasonal flu goes through annually.

Three times in the last century the influenza virus changed into a new strain in this way. Each time, the result was a global pandemic with a large toll of illness and fatality.

The big one was the 1918 Spanish flu pandemic. It affected vast numbers of the world's population and is thought to have killed up to 50 million people between 1918 and 1919. It is considered to be one of the deadliest disease events in human history.

More recently, two milder flu pandemics have occurred. Asian flu in 1957 is estimated to have killed 2 million people. Hong Kong flu in 1968 caused approximately 1 million deaths.

Pandemic strains have been associated with serious illness and death in the young and healthy more often than seasonal strains. The Spanish flu death rate was higher among healthy young adults than in the over 65s.

The reason for the severity of pandemics is the novel form of the virus that causes them. Since no-one has been exposed to the strain before there is no baseline immunity in world populations; whereas a certain level of immunity exists against the seasonal flu viruses due to the fact that they change more slowly and remain at least partially recognisable to immune systems across the globe. Even a low level of immunity can ameliorate the severity of the disease.

A total lack of immunity is the factor that places a bout of pandemic flu into a very different order than everyday flu.

What To Do »»

^ Top