Pandemic flu outbreak expected, Canadian Press (Nov 9, 2004)

Toronto — The world is at an unprecedented time in the history of influenza with the threat posed by the current widespread outbreak of the H5N1 avian strain in Asia, a conference on global infectious diseases was told Tuesday.

Few tools exist to contain the virus, which has decimated poultry stocks across broad swaths of Asia and has defied the experts by jumping directly — and with lethal impact — into several species of mammals, including humans.

At least 44 people have been infected with the virus; 32 have died.

“We're very limited in what we can do for this virus,” Dr. David Heymann of the World Health Organization told participants at the two-day conference, organized by the University of Toronto and St. Michael's Hospital's Centre for Global Health Research.

“This virus is rapidly spreading around the world, the fear of course being that H5N1 from chickens will enter a human and . . . reassort to form a human influenza virus which will then have genetic characteristics of a human virus, spread rapidly around the world and cause deaths,” said Dr. Heymann, executive director of the WHO's communicable diseases division.

The process Dr. Heymann was referring to would mark the start of a new influenza pandemic, an event most flu researchers believe is both inevitable and overdue.

In the 400 years of recorded influenza history, pandemics have occurred on a regular if sporadic basis. The longest period between pandemics has been 30 to 40 years, noted Dr. Allison McGeer, an infectious diseases specialist at Toronto's Mount Sinai Hospital.

The last pandemic was 36 years ago, the Hong Kong flu of 1968.

“It's going to happen,” Dr. McGeer told conference delegates. “The only surer things than influenza pandemics are death and taxes.”

A flu pandemic occurs when a strain of influenza to which humans have no innate immunity breaks out of nature and acquires the ability to transmit easily from person to person.

It would sweep the globe within months. Based on the experience of the three pandemics of the 20th century, a third or more of the globe's population would be expected to fall ill. A pandemic, even one caused by a mild strain, would be expected to kill millions, experts warn.

The spectre of a pandemic with the extraordinarily virulent H5N1 strain is making for sleepless nights in the community of influenza researchers.

“There is reason to hope that as these viruses become adapted to humans, that they may become less virulent. But there is absolutely no surety that as they become adapted to humans that they will become less virulent,” Dr. McGeer warned.

“And there remains the possibility that when we face the next pandemic, that we're going to be facing a pandemic that will be as severe as the 1918-19 pandemic.”

That pandemic, more commonly known as the Spanish flu, killed an estimated 20 million to 50 million people worldwide in a mere 18 months.

Experts say the best hope to contain the damage would be vaccine, but vaccine takes months to make. And, as this year's shortage in the United States illustrates, supplies can at best protect a fraction of the world's population. The total global annual production capacity is 260 million doses of flu vaccine.

The WHO has called a summit of vaccine manufacturers for later this week in the hopes of finding ways to ramp up production.

“With influenza we don't have the tools we need today to deal with epidemic influenza,” Dr. Heymann cautioned, referring to the annual outbreaks of flu.

“We certainly don't have them should there be a pandemic.”