When you hear "pandemic" you might think of past catastrophes like the Spanish flu or the Asian flu, which affected millions worldwide. But the term "pandemic" only describes how a disease is spread, not its severity. A pandemic occurs when there are more cases of infectious disease worldwide than normal.

The past

In 1918, the Spanish flu swept across the globe, taking an estimated 50 million lives over the course of about 12 months. It was an extremely deadly virus, capable of killing healthy individuals within a day, and no pandemic has reached the likes of it since.

The world saw its next flu pandemic in 1957, the Asian flu. The death toll was somewhat less than for the 1918 pandemic, with about 2 million worldwide deaths. Technologies had improved - the virus could be identified and a vaccine could be produced in response. The Hong Kong flu of 1968 was the last and mildest influenza pandemic of the 20th century, with the number of deaths totalling 1 million.

H1N1 flu virus

The recent outbreak of influenza A H1N1 virus (human swine flu) prompted health authorities to take precautions in line with the World Health Organization's (WHO) recommendations for pandemic preparedness based on its 6-phase system of pandemic alerts. Since the H1N1 virus is a new strain of virus that has spread to many countries, public health authorities are exercising much caution.

Are we overreacting?

Experts believe we are overdue for a pandemic, so any new diseases that can be spread among humans are responded to with vigilance. As the saying goes, "better safe than sorry." Pandemic "threats" have occurred over the past 30 years, but none of these have escalated to pandemics.

In 1976, a small outbreak of swine flu in Fort Dix, NJ, led to the vaccination of millions of Americans. The outbreak was contained and a pandemic never occurred. More recent scares of avian flu were handled swiftly and potential catastrophe was prevented by slaughtering all chickens in Hong Kong, where the flu first appeared in humans.

The seasonal influenza affects millions of Canadians annually; thousands die of the flu and related complications. Fortunately, most cases of the H1N1 flu virus have been mild and did not require antiviral medications. The Canadian health authorities work alongside the WHO, both of which are experienced in handling pandemics, to control the spread and impact of the H1N1 flu virus.

So what can you do?

The simple act of washing your hands and maintaining proper hygiene effectively prevents the spread of many infections. Remember, an ounce of prevention is worth a pound of cure.

Learn how to properly wash your hands. For more information on the H1N1 flu and tips on preventing infection, read "H1N1 flu virus (human swine flu) and you."

For more information on the WHO's pandemic alert phase system, read "Decoding WHO's pandemic levels."

Jonathan Lu