Epidemiologists and virologists are concerned about the resurgence of the H1N1 flu virus in the northern hemisphere come the start of our flu season in the fall of 2009. While the virus is making its appearance in the southern hemisphere, in time for their flu season, the chance of genetic mutation remains high. As it stands, the virus has currently made its way to Australia  where public health officials have confirmed over 100 cases, almost a doubling of cases from the day before.

A similar pattern occurred during the 1918 influenza pandemic: that virus first appeared in a mild form in the spring and by the time it reemerged again in the fall, it had mutated into a particularly virulent strain to which people had no immunity. The 1918 influenza pandemic ended up killing around 50 to 100 million people and infected about 1/3 of the world’s population. 

What concerns epidemiologist today about the H1N1 flu virus is the fact that this is a “novel” virus, meaning, that most people have no immunity to it. (Interestingly, researchers have found that older adults 60+ may have some protection to the current virus because they have lived long enough to have had exposure to similar strains of virus.) Hence, young adults, children and infants remain at high risk for complications related to the virus.

The fact is, no one knows how lethal the virus may become but what is known is that viruses easily mutate and that few of us have any protection from this particular viral strain if it goes lethal. That’s why it’s important for us not to become complacent about the seriousness of this strain.