No-one should be all that surprised by the recent emergence and spread of the Swine Flu virus from Mexico that looks likely to have pandemic potential. Experts have for years been saying that a flu pandemic was inevitable — and that it was just a matter of when, not if, the next major flu pandemic would strike.

Flu pandemics come in cycles — and we have long been overdue for one. Though public attention has for years been focused on avian influenza (H5N1) as the likely candidate for the next pandemic strain of flu, experts have consistently been warning that it was not unlikely that the next pandemic would arise from a different strain of influenza altogether. Pig flu may have suddenly stolen the show from bird flu– but this was not to be unexpected.

Fears about flu pandemics are commonly associated with the great Spanish Flu pandemic, which killed somewhere between 20 and 100 million people worldwide in 1918-19. The Spanish Flu killed more people in a single year than any other disease in history — and more Americans than were killed in battle during World War I, World War II, the Korean War, and the Vietnam War combined.

On the one hand, influenza can be quite an ordinary disease — we all suffer from the flu every now and then. Pandemic flu is somewhat different. Pandemics are worldwide epidemics that periodically occur because the influenza virus is changing constantly as a result of the fact that it is particularly prone to genetic mutation. When an animal — usually bird or pig — version of the virus mutates into a form that makes it transmissible between humans, the resulting virus is more dangerous. We have less immunity against it because we have never been exposed to it — or its nearest flu relatives — before.

On the other hand, even pandemic flu is not plague. One of the biggest dangers associated with pandemic flu is that the media, the public, and policy makers will over-react to it. New infectious diseases often lead to unnecessary hysteria — and hasty, irrational, and overly-draconian policy responses.

Though estimates range widely, the 1918 flu is commonly thought to have killed 40 million people. That would be roughly (only) 2 percent of the population at the time. It is true that many of these people were young and healthy — but many were also old or already sick with other illnesses.

The bottom line is that even if the next flu pandemic is as deadly as the worst flu pandemic in history — which is unlikely based on statistical probabilities — a large proportion of people will become infected, but only a small proportion of the population will die or suffer permanent harm.

At the end of the day, even pandemic flu is still just flu. Influenza is simply not the kind of disease that wipes out populations — as the Black Death eliminated one third of the European population between 1347 and 1350.

When it comes to flu, therefore, perhaps the only thing to panic about is panic itself. And panic should not arise if policy makers and public health officials do a good job communicating to the public about the nature of the disease and the measures that can be taken to reduce chances of infection — and if they avoid unnecessarily resorting to draconian public health responses such as isolation and quarantine enforced by the military or other security forces.

We should recall that measures like these spurred riots in China during the SARS crisis of 2003. There may be a place for coercive public health measures such as isolation and quarantine, but once a flu pandemic has taken root and is spreading freely across the global population — as the current Swine Flu seems to be doing — it may already be too late to contain it via measures like these. Such measures are, in any case, notoriously lacking in evidence regarding their effectiveness.

Also lacking in evidence is the effectiveness of masks as a means of infection control. It is a tragedy that we don’t know more about whether or not mask-wearing provides substantial protection against flu. Presumably the only reason we do not know more about this is that no one has bothered to spend the money required to study it properly.

Too much medical research is left in the hands of profit-driven pharmaceutical companies that aim to develop patentable products that they can sell for lots of money. We need additional support for research on other (low-tech) kinds of interventions — like mask-wearing — that don’t promise much in the way of return-on-investment for private industry.

I suppose this means that governments should be directly funding more research like this. Now would be a good time to start — opportunity knocks.

Dr Michael J Selgelid is Deputy Director of the National Centre for Biosecurity at The Australian National University.