We are now a few weeks into the “second wave” of the Influenza A H1N1 “variant” or H1N1v (a.k.a. swine flu or the imprecise “H1N1”) pandemic. With the media's focus squarely on the here-and-now, we hear about absentee rates, fatalities, vaccination fiascos, queue-jumping hockey players, and so on. At least 115 people have died in Canada so far, and the health burden of the pandemic has been significant. But with a low fatality rate, and minimal chaos and catastrophe, there is a growing tendency to think that H1N1v has been overhyped, a tempest in a teapot.

There is something to be said for this point of view: when compared with other health risks, H1N1v has certainly received more than its fair share of attention, and the fear and anxiety are taking their toll on many. But there are legitimate concerns about this strain, and we can learn a lot by keeping track of what the disease does, how it changes over time, and how we respond to it. As the public health and media overreaction breeds its own overreaction, we risk turning our attention elsewhere and being unprepared for the next surprise influenza sends our way.

So why should we still be concerned about H1N1v?

Because it can be fatal, and “underlying conditions” are not that uncommon. According to the best available large-scale studies, two important risk factors for H1N1v are asthma and morbid obesity, both of which are on the rise. Other risk groups, such as children under the age of two and pregnant women, have been well publicized. Beyond this, some recent research suggests that underlying factors play more of a role in pandemic flu lethality than they do for the seasonal flu. Even if an individual is not in one of the named risk groups, shouldn't they still try to break the chain of infection that will otherwise lead to a high-risk individual?

Because it's the new kid on the block. It is still hard to decide which groups are at greatest risk: one need only look at the conflicting priority groups between provinces to see this. The elderly appear to be less likely to be hospitalized with H1N1v, but more likely to die if they do end up in a hospital. Although morbid obesity appears to confer higher risks, it is unclear why this is the case, or whether the risk is diminished but still present for people who are obese.

So even though the 2009 bug shares a name with the strain that has been known since 1918, it clearly has some distinguishing biological features. And although molecular biology can tell us a great deal, it is still very difficult to link differences in viral behaviour to differences in the underlying genetic sequence. The single change that can make a virus resistant to the flu medication Tamiflu is well known, but the virus remains a giant question mark in many ways.

We also have no idea about where H1N1v is going, in evolutionary terms. Different flu strains can swap genes at will if they infect the same host at the same time, catching our immune systems completely by surprise. The “nightmare scenario” would see H5N1, which is about 60 per cent lethal but rarely transmitted, mixing with a seasonal flu strain to produce a highly transmissible and deadly novelty. Luckily for us, this particular flu remix appears to be non-viable. But what about H1N1v? It is encouraging that no such beast has yet appeared, but we simply do not know what additional risks are posed by the new virus in the medium- to long-term.

Because it's a dress rehearsal for a “real” pandemic. The public response in the past few weeks has tended toward excessive fear and anxiety, which has led to massive queues for vaccines that were in short supply. The public response has nonetheless been orderly. But what if the fatality rate is five or ten times higher the next time around? Will you stand in line with people who are coughing and sneezing? How will priority groups be determined and enforced? How will people interact at the grocery store when schools and other public buildings have been shut down?

I'm not trying to make you panic! H1N1v is highly contagious, but it's not Captain Trips and shouldn't be treated as if it is. On the surface, one might be tempted to kick up one's feet, bid a fond adieu to the alcohol-based sanitizers that have had such a good year, and start rewriting the story in our heads so we'll have something to impress our grandchildren with in 40 years' time. But H1N1v is new, and defies much of the conventional flu wisdom. We must learn everything we can about this pandemic to prepare ourselves for next time.