The outbreak of H1N1 influenza in Mexico has rekindled concerns about a global influenza pandemic. The response has been all too predictable. The World Health Organization has raised the level of pandemic alert and announced that "all of humanity" is under threat. The Public Health Agency of Canada has advised people not to travel to Mexico. And with a (mild) case appearing in Ottawa yesterday, the media are once again feasting on the story.

The facts, however, are more prosaic. Admittedly, when first reported two weeks ago, the events in Mexico were quite alarming. It seemed a new influenza virus was causing serious disease, particularly in young people. This is precisely the scenario we would expect with the beginning of a new pandemic.

Since then, however, almost all the news has been good news, even if it hasn't been presented that way. The most important events have been the ones that haven't happened. It's not entirely clear exactly what is going on in Mexico, but one thing is certain: H1N1 is not behaving like a new pandemic strain.

We now know that the first cases of H1N1 date from early March. This should put Mexico at or even past the peak of its first wave of infection. According to standard pandemic models, Mexico should be seeing about 1,000 deaths each day. Obviously, this is not happening -- not even remotely close. The illness caused by this virus seems to be very mild. And the virus itself may not be so "new" after all.

Some tourists returning from Mexico have brought the virus back with them to Canada and elsewhere. This is hardly surprising. What is more important is that the virus is showing no ability to transmit efficiently here, at least at this time of year. The WHO's notion that the disease is "spreading" every time a visitor brings it to a new country is misleading.

The story is not over yet. We need better epidemiology from Mexico and continued surveillance here. But, overall, the news is now very encouraging. While predictions about the future are inherently hazardous, two scenarios seem most plausible. The virus may die out completely because it is just not quite infectious enough to survive in human populations. Alternatively, it may become established as our dominant seasonal strain. This really shouldn't worry us, however, because the disease is so mild.

So why isn't this message getting out? The sad truth is that there are strong vested interests flourishing from the fear of pandemics. Over the past five years, pandemic planning has mushroomed at all levels of government. Public health agencies have received substantial additional funding for pandemic preparations. Some professionals are building careers as pandemic experts. Good news about pandemics is simply not welcome.

Now is a good time to re-examine the underlying premises of these pandemic fears.

Influenza is an important infectious disease. It regularly kills more Canadians than any other infectious disease. Influenza pandemics do happen -- triggered by the appearance of new strains for which we have no immunity -- but many of our fears are based on misconceptions.

We should dispel the idea that an influenza pandemic necessarily means a catastrophe. The last two pandemics -- the 1957 "Asian" flu and the 1968 "Hong Kong" flu -- were not very different from seasonal influenza except that more people were ill. The 1918 influenza pandemic was worse, but much of the information about it is very sketchy. More to the point, a lot has changed since 1918. We have vaccines, antiviral drugs, antibiotics (most influenza deaths are from secondary bacterial pneumonia), intensive care units and, most importantly, far better general health. Even a 1918-style pandemic should not be a cause for undue alarm.

We should also discard the perception that an influenza pandemic is an emergency. Pandemics unfold on a time-scale of weeks to months; not hours to days. A pandemic can't be "contained," only responded to. In other words, public health authorities should learn to take a little more time to gather and analyse information before raising pandemic alerts or launching pandemic plans.

We need to understand that influenza viruses are not going to suddenly change and become more virulent. This open-ended threat -- usually couched with the term "mutation" -- is a theoretical possibility with any infectious disease. In practical terms, however, it is so rare that it doesn't merit serious consideration. It's the stuff of science fiction.

Once we correct our misconceptions, an influenza pandemic loses much of its terror. It is something we need to be prepared for -- and generally are prepared for -- but not something we should lie awake at night worrying about.

What lessons should we draw from this latest false alarm?

First, we need more and better information before reacting. The Mexican situation looked alarming at first. A little digging revealed a very different and more reassuring picture. There is no point in acting in haste.

Second, public health needs to stick to its principles, regardless of public and political pressures. Canada protested strongly when it was the subject of a WHO travel advisory during the 2003 SARS outbreak. We argued, correctly, that these advisories accomplish nothing except to spread fear and damage the economy of the country targeted. So why did Canada rush to issue a travel advisory on Mexico? It was irrational and unfair. Let's not make that mistake again.

Third, the media must be more critical. How many pandemic false alarms do we need (remember "bird flu" -- the last great threat) before reporters start asking tough questions? How many times do the voices of catastrophe need to be wrong before we doubt their message?

Dr. Richard Schabas is the medical officer of health for the Hastings and Prince Edward Counties Health Unit. He was Ontario's chief medical officer of health from 1987-97.