The Basics, Part 2: Why You Should Be Concerned

What is the big deal with this new swine flu? After all, at least in the United States, no one is dying from this. Nothing came of the bird flu scare of 2006. The swine flu scare of 1976 turned out to be nothing.

Let me address each of these objections. Then I have some other things to point out.

"At least in the USA as of April 27, no one is dying from this."

This is quite true. As of suppertime on Monday, April 27, no one in the United States was determined or even rumored to have died from the new swine flu. Unfortunately, this should not give us any comfort.

It is in the nature of viruses that their genetic material has the potential to mutate into different forms. However, different viruses have different degrees of potential, when it comes to mutation; some will mutate frequently, and into radically different forms, while others will mutate infrequently, and not change too much. The new swine flu is caused by a virus that is composed of a previously unseen combination of elements of four other viruses. No one knows how this virus will change, or what it's potential is. It is entirely possible that it will not mutate at all, or mutate into a less dangerous form, or mutate into something even more lethal and more contagious.

It is true that one of the big mysteries at present is why so many have died in Mexico, and no one in the United States. There are a couple of possibilities here, none of them cause for comfort:

• The "Too Soon" Hypothesis. It might simply be the case that the virus has been active in the United States for too short a period of time to have killed anyone. Mexico has seen about 1,995 documented cases of flu recently (since some time in March), with 149 recent flu deaths. Let's take one of the worst-case scenarios: all of the flu cases and fatalities were caused by the new swine flu. This would yield a fatality rate of almost 7.5%--an astonishingly high fatality rate for influenza. However, we only have about 48 cases of flu in the USA that we know were caused by the new swine flu. Even with a similarly high fatality rate, we would only expect to see maybe 3 or 4 deaths, and that would not be for some time, either. Basically, there may not have been enough time for fatalities to show: this is the alternative scenario, the "Give It Time" hypothesis.

• The "Poorer Nation" Hypothesis. It may be that the relatively poorer level of nutrition and health care in Mexico, relative to the United States, is to blame here. However, this will be no protection for the US. The first identified cases in the United States were business or pleasure travellers to Mexico, who had the financial resources, not only to go abroad, but to get good, attentive health care. However, the US has millions of people who have no health coverage, and who are suffering economically from the Great Recession; they may be relatively malnourished, and may be trying to tough out the flu without health care at all--at this very moment. They wouldn't appear on the radar of the health authorities until they seek health care, and that may not happen for many of these people for some time. (Even if you, the reader, have health coverage, that won't necessarily protect you as much as you'd like: if the less fortunate get the flu, they may develop secondary infections such as pneumonia, which can be passed on to you along with the flu.) Thus, it may be that there are many more infected in the US than we know about, people too poor to seek health care; this is the alternative scenario, the "Hidden Infections" hypothesis.

• The "Just Lucky" Hypothesis. Perhaps we're just lucky, and the virus mutated to a less powerful form before it infected the cases in the US. I don't think so, and here's why. Normal flu kills people, but usually a fraction of 1% of those infected, and those are mostly those with compromised or immature immune systems: infants, the elderly, people on immunosuppresant drugs, and so forth. The Mexican authorities noted that their flu fatalities were primarily among the healthy and strong young adult population, aged 20-40. This is troubling because this is precisely the population that has been hit in previous flu pandemics, most notoriously the so-called "Spanish Flu" of 1918. (In a future post, I'll explain why this group is hardest hit; briefly, their immune systems are so vigorous that they go into overtime and actually overwhelm the body of the young adult.) Details are skimpy, but the people known to be infected in the US by the new swine flu so far seem to fall outside the target age range for pandemics: over half the US cases are just a bit too young (high schoolers in Queens, NY), and the business travelers may well be older. Thus, the people most at risk were not among those first infected in the US, although they may very well be infected at this point. This is the alternative scenario, the "age range" hypothesis.
  

In sum, yes, no one has died of the new swine flu in the USA yet. However, this should not make us complacent at the moment.

"Nothing came of the bird flu scare of 2006."

Yes, lots of people got scared because of the avian or bird flu incident of 2006, and yet nothing came of it. However, if you go back and look at the news pieces that emerged from that incident, you'll see that there was a good reason for that, a reason that does not apply with the new swine flu of 2009. The bird flu of 2006 was never shown conclusively to be transmissible from human to human; to put it simply, infection seems to have required some sort of physical contact with infected birds (like being a chicken farmer). However, in 2009, we have conclusive proof that human-to-human transmission is happening. That is why the United Nations World Health Organization (WHO) raised its pandemic threat level to Level 3, and then to Level 4. (It's a six-point scale, where Level 6 is a full-blown pandemic.)

"The swine flu scare of 1976 turned out to be nothing."

Yes, the swine flu scare of 1976 turned out to be nothing; more people died of bad reactions to the flu vaccine than from the flu. However, although the name is the same, the 2009 organism is different from the one seen in 1976. The organism that we are seeing in 2009 combines genetic components of human flu, avian or bird flu, and two strains of swine flu, in ways that have never been seen before by scientists. It is just an accident that it happens to have the same public label--'swine flu'--as the weak organism seen in 1976.

Further Reasons To Be Concerned

I wish that were it, but it is not. There are troubling echoes in the 2009 swine flu incident that reminds epidemiologists of what may have been the worst pandemic seen in recorded history: the 1918 Spanish flu. In the course of a single year (1918-1919, the tail end of World War I, which overshadowed the flu in the news), this pandemic killed between 20 million and 100 million people around the world (almost certainly much closer to the high end than the low end of that estimate). This is more people than were killed during the Black Death of 14th century Europe--and all within the bounds of a single year.

(The photo above shows police in Seattle during the 1918 epidemic, wearing face masks.)

For the last thirty or forty years, as biomedical science has come to understand viruses better, epidemiologists have been predicting that it is just a matter of time until something like the Spanish flu appears again, causing a global pandemic that could be even worse--because modern transportation can help the virus travel farther and faster; because now more people are crowded together into cities, making infection much more efficient. Although we now have antiviral agents to fight the flu, we only have a few. (Antibiotics work against bacteria, not the much, much smaller viruses.)

So, is the new swine flu of 2009 like the Spanish flu of 1918? There are two areas in which there is an unfortunate resemblance:

1. Infection patterns. The Spanish flu was a shock to medical workers, as it killed healthy young adults. As I pointed out above, this is the same pattern seen in the new swine flu.
2. Fatality rates. The Spanish flu killed about 2.5% of those whom it infected, a fatality rate at least three to five times higher than the fatality rate of normal human flu. As I pointed out above, although data are sketchy, the new swine flu seems to have a fatality rate in the range of Spanish flu--and maybe worse.

Conclusion

I have given reasons why you should be concerned about the new swine flu. Even if the new swine flu of 2009 peters out, as we all hope it will, it is still just a matter of time until something like the Spanish flu emerges again. New swine flu or new Spanish flu, you need to prepare now to deal with this threat. I describe how to do that in the post "The Basics, Part 3: What You Can Do." (It will appear in this blog just above this post, if you are looking at the blog in its entirety.)

(The photo, of police officers in Seattle, December 1918, wearing masks made by the Red Cross during the influenza pandemic, was obtained from Wikimedia Commons, and is in the public domain in the United States.)