The Flu

I got my flu shot yesterday. So bring it on, flu season!

"The Flu" is a tricky term. I've found that its useage amongst doctors and laypersons often differs, which makes communication difficult at times. Often I will have a patient come into my office and say, "I think I've got the flu", and they will be referring to any wide number of symptoms including muscle aches, headaches, vomiting, diarrhea, fever, runny nose, etc. etc. Or sometimes they will even be more specific, stating "I've got a bad stomach flu" which usually refers to the nausea, vomiting, and diarrhea aspect of things.

However when a doctor uses the word flu they are referring specifically to influenza virus, the symptoms of which DO NOT typically involve GI stuff (nausea, vomiting, diarrhea--at least this is true in adults) and usually involve more severe fever, muscle aches, sore throat, and headaches than are found with your typical upper respiratory tract infection/cold. I've never had the flu, but I'm told that people who DO get it "wish they could die". It's fairly serious.

The "flu shot" is an inactivated vaccine (the viruses have been killed before it gets injected) which is comprised of the 3 most common strains of flu virus that year--one from the most common strain of influenza A (H3N2) virus, one from the most common strain of influenza A(H1N1) virus, and one from an influenza B virus. "A" and "B" refer to the two most basic types of influenza virus. The "H" and "N" nomenclature describes which type of hemagglutinin molecule (of which there are 16 types) and which type of neuraminidase molecule (of which there are 9 types). The vaccine is not perfect (there is still the possibility of getting the flu even if you get the vaccine) but it's pretty good & it's the best treatment we've got. There are antiviral medications out there in pill form (e.g. amantidine & oseltemavir, or Tamiflu) but they generally need to be taken as soon as you start having symptoms or they don't really help. Fortunately the flu vaccine shortage situation we had last year is much improved (or at least it seems to be within my own health care system, and I've heard less about it in the news). It usually doesn't even hurt too much, unless you're a wussy (see picture on right).

Which brings me to my next topic: The avian flu virus, and should we all be freaking out about it right about now? Well, yes and no. The avian flu virus is an H5N1 influenza A virus, meaning that its "molecular signature" is extremely different from that of the influenza viruses which typically infect humans. Our immune systems recognize this virus as a foreign invader and ramps up its immune response something nasty. Not suprisingly, our flu vaccine doesn't work (remember, it's made against the most common strains of human flu virus). It has resistance to most, but not all, of our oral flu medications. In 1918, something similar happened in which the flu virus jumped from pigs to humans, causing a Flu Pandemic resulting in the death of between 20-40 million people in a year's time, eclipsing the death toll from both World War I & the Bubonic Plague. All of these things I'm telling you would seem to suggest a strategy of freaking out. However, there' s some good news. For one, the disease has not yet occurred in Europe or the United States and has been thus far restricted to Southeast Asia. Zero recorded cases thus far. Also, while the disease has scarily been observed to pass from birds to humans, it has not yet been observed to pass from human to human. It could certainly evolve to do so, but thus far it hasn't yet. Also, researchers are currently working on a vaccine for the avian flu. Our ability to make a decent flu vaccine in a short time is pretty good--the mass-production and distribution of such a vaccine is a whole other issue--but generally speaking the technology is there. So let's hold off on the freaking out for right now but take the threat seriously enough to come up with a worst-case scenario plan. Okay, Commander-in-Chief? Unless of course, you can think of any wars we could fight which would be more beneficial to us as a country...

But that's another issue for a later time...