OH MY GOD!!!!! IT'S THE SWINE FLU!!!!!!!

I have been reading so much media hype over the swine flu, that my head is beginning to hurt. For my readers that have been living under a rock, there is apparently a horrible flu in Mexico that has killed a few people while simultaneously sending the entire world into a frenzy. Infectious disease is certainly not my forte, but I can explain a little bit about influenza. I can also explain a little bit about my personal opinion on this disease.

What lay people consider the flu is actually a variety of similar ailments. The most common causes are from a couple of different types of influenza virus. Similar symptoms may come from the parainfluenze virus, as well as a couple of other outliers. The only "flu" that is actually the flu comes from influenza virus. This particular virus that is causing the swine flu is of the Influenza A type of influenza virus. This type of virus may express a variety of different antigens. The antigens to which antibodies are commonly made are generally knows as H and N antigens. The variation within these antigens is why there are so many different strains of flu and why unlike say the chicken pox, you can get infected with the flu virus repeatedly. Different influenza viruses can exchange DNA with each other to produce genetically distinct daughter strains and promote variation.

Humans are not the only species that can be infected by the flu. Strains of the flu can affect other animals, including species of birds and pigs. Generally, bird flu and pig or swine flu are not infectious to humans. However, a flu that can afflict these species may exchange some DNA with human flu. Occasionally, a flu that is infectious to another species may, either by spontaneous mutation or by exchange of DNA with a human virus, become infectious to humans. Most of the time, this infection is isolated to a specific person or group of people that have contact with the infected animal or animals. However, there are cases where this new infection will further mutate to allow transmission from human to human. This introduces a bunch of new DNA into the human influenza genome.

Humans usually walk around with some immunity to the flu. We have a part of our immune system that fights viruses in general, but most humans have been exposed to flu before, and thus most people walk around with additional immunity. The different strains of influenza are distinct enough, that they can re-infect the same host. However, they are similar enough that a previously exposed host can usually mount a partial response to the infection. We could think of this as damage control. You're sick with the flu, but your immune system can hold it at bay with relative ease due to its similarity to other strains that you have been exposed to. You are also part of the way towards developing immunity to the new flu, so the response is quicker.

In cases where there is exchange of DNA from an animal to a human flu (or worse yet when an entirely new flu virus crosses over from animal to human), people will lack this immunity. This gives the infected person fewer resources to hold the disease at bay up front, and it takes longer to develope a specific response to the virus. The VAST majority of the time, this makes for a bad long lasting flu. It is usually NOT fatal. However, occasionally an extremely virulent strain will cross over, and the previously unexposed human population will have very few big guns to stop it up front. Major flu pandemics (such as the flu of 1918) can be the worst-case scenario result of this sort of event.

There are a few more facts to keep in mind about the flu. Common everyday influenza is already the bane of the very young and old, the immunocompromised, and the sickly. Every year, 30,000 people will die in the US from the common everyday flu. Most of these people will fall into one of the above categories, though there will be some who will end up susceptible in the not obviously sick adult population. To put it into perspective, the flu kills as many people every year as 6 world trade center bombings.

The fear and panic over the swine flu seems to come in large part from the fact that a number of young people have died in Mexico, and the strain seems to be a swine strain of the flu that has crossed over to humans and mutated so as to be transmissable from human to human. I agree that this little set up is exactly how most pandemic flu starts. However, there are some things which make me seriously doubt the current degree of crisis, and more importantly, make me doubt whether this will really turn into a global pandemic spreading death in its wake.

The official number of deaths in Mexico currently sits at ~7 per the WHO, with estimates up to 200 of actual victims. There are over 27 known cases of flu in the country, but we all know that the majority of cases probably never sought medical attention or made an official statistic. This 27 number is only laboratory confirmed cases. These are people who made it to the doctor, had signficiant symptoms, were suspected, were tested, and came back positive. We have no way to assess these numbers. Were these really healthy people? Is the number really 7 or 200? Is it possible that there is a group of immunocompromised patients that got hit with the flu?

The flu has currently spread, per the WHO website yesterday, to 9 different countries. The CDC this morning has confirmed 109 cases of swine flu in the US, with one solitary death. This death, though unfortunate, was in a toddler in Texas at the age where children may be susceptible to death from any flu. No one outside of the US and Mexico has died of this flu. The fact that no is dying of this flu outside of Mexico alone makes it suspect. Are we dealing with two different strains of swine flu? Is there some other contributing public health disaster in Mexico to which we are not privy? Are the official deaths all immunocompetent hosts?

Lastly, this whole thing is essentially starting after flu season. The flu just doesn't generally reach peak virulence when it starts this late.

Here's what we should do (this is if someone were to ask me of course). We should work on a vaccine for this particular strain to offer to individuals who are likely to be susceptable before next flu season. This flu very well may attack at the beginning of the next flu season. We should also make sure that there are sufficient stockpiles of anti-viral drugs to address the possibility of a bigger problem. We should really only use these when people are very sick or start dying in real numbers. The last thing we want to do is breed resistance in a virus that seems to be doing minimal damage in our country now, only to have it develop resistance if it becomes more virulent. We should also watch the virus and its spread. A sudden rise in flu related death should necessitate further investigation.

Here's what we should NOT do. There is zero reason to panic at this point. We should not be stockpiling Tamiflu and N95 masks. We should not be cancelling events. We should not be living in fear. Every few years, we panic over a new strain of flu (remember the whole avian flu debacle). These sorts of things happen all the time, and it would really be ridiculous if we all shut down ever couple of years over the small possibility that a flu could become a pandemic. Most flu pandemics come from the crossing over of flu from species to species, but most crossing over doesn't result in a pandemic.

As I have always maintained on this blog, one of the few legitimate roles of government in healthcare is the control of infectious disease. It is appropriate for them to watch this. Remember however, that the vast majority of infected people have probably never been tested or even sought medical attention. The death rate amongst known cases (which are probably the worst cases) is still less than 1%. Let's keep this in perspective. Right now, the rate of death from this swine flu in the US really isn't any higher than the rate from regular flu (something we do not panic about).

It is smart to stay vigilant, but we cannot panic over every potential problem, because the possibilities are endless. If I see one more person walking around in a surgical mask (a mask that probably doesn't protect the person) here in my state where we have no cases of the swine flu, I may lose it. The panic is ridiculous. Could a swine flu pandemic occur? Sure. So could a nuclear war with China. At this point, I don't see a reason to panic about either of them.