Musings of a Dinosaur

A Family Doctor in solo private practice; I may be going the way of the dinosaur, but I'm not dead yet.

Sunday, September 20, 2009

Everything You Need to Know About the Flu

Dear Innuendo Ultimate,

Earlier today I promised to tell you all about the flu, but those first two games were so close and hard fought -- and we were all so wiped by the end of the third one -- that I never got around to it. Here's what I wanted to tell you:

Influenza -- flu -- is caused by a respiratory virus. That is, a virus that comes into contact with the inside of your nose or mouth (the top of your respiratory tract). It's passed from person to person through "respiratory droplets" produced when you cough, sneeze, or wipe your nose on something that someone else then touches, and in turn touches to their own nose or mouth.

The disease it produces is different from just a cold. More than just a little sore throat, runny nose, and cough, flu usually produces a fever (temperature over 100 degrees, taken by mouth), body aches, and headache, along with a scratchy throat, cough, and stuffy or runny nose. It's not subtle. Patients often tell me they feel like they've been hit by a truck. "Body aches" means everything hurts; lots of people say, "Even my hair hurts." Flu really knocks you on your ass. If you're not sure you have the flu, you probably don't.

Most people get over the flu just fine, though it can take longer than you want it to (up to 10-14 days), but it can weaken some people enough so that they get other infections (like pneumonia) on top of it. About 30,000 people a year, on average, die from the flu; usually the very old, the very young, and people with medical conditions like diabetes and asthma that make them susceptible to flu complications.

The flu virus mutates a lot. Even through the regular flu season (fall/winter, when it's cold, and people -- and their respiratory droplets --cluster inside together) the virus can mutate slightly. Once you get a specific flu virus, you form antibodies to it; this means you can never get it again. Other mutations of the virus can still make you sick, though. Still, over a lifetime, you accumulate immunity to the various versions of the virus that circulate each year.

Different mutations of the virus act differently. They may be harder or easier to catch ("infectivity"); they can cause a milder or more severe illness ("virulence"). These variables are independent of each other.

Every year the CDC chooses three flu strains they think will most likely circulate that year, and they make a vaccine against those three. We call this the "seasonal flu vaccine", and it changes each year. In general, it is recommended for those groups above (old, young, and with certain medical conditions). I tell people who ask me that I recommend it for anyone who doesn't want to get the flu.

Here's what's different this year:

Back in the spring, a new ("novel") flu virus mutated from a version that infects pigs (hence the "swine flu") and began infecting people. Named for the proteins on its surface, it's known as H1N1 (also called "hinny" by morons who think that's a word). So far, this version of the virus is very contagious (highly infective; easy to catch) but not terribly virulent (causes mild disease). Because this form of the virus hasn't circulated for many years (probably since the 1950's), it turns out that younger people are more susceptible to it than older people. Lots of people have been getting "swine flu" all summer.

So what's the big deal?

Back in 1918 there was a huge pandemic (pandemic = worldwide epidemic) of H1N1 flu that killed an estimated 50,000,000 people. What was worse was in addition to the very old and very young, an unusually large number of young, otherwise healthy people died from it. No one is quite sure why. Probably a lot of it had to do with the general state of medical care back then (no antibiotics, ventilators, and all sorts of other fancy supportive care). Also, it was the height of World War I, with troop ships moving lots of soldiers all over the place, spreading the virus like crazy while they were all crammed together. Many people think it was because the virus was novel, so very few people had any immunity to it. Still, there seemed to have been something about that particular virus that made it much more virulent than others.

Remember how I said that the virus can mutate even during the same flu season? There is the concern that although the current version of H1N1 isn't all that virulent, it could mutate and become much more so. We're unlikely to see 50 million worldwide deaths again, but it could certainly get pretty bad.

It takes about 6 months to make seasonal flu vaccine, so by the time H1N1 was identified, it was too late to include it in this year's mix. They did manage to make a separate H1N1 vaccine, though, and it should be available by mid-October. It's recommended for everyone aged 6 months to 24 years, pregnant women, caretakers of babies under 6 months old, and anyone with medical conditions that make them more susceptible to flu complications. (Also health care workers; I'm not sure if that technically includes athletic trainers.)

The flu shot does not contain flu virus. It cannot give you flu. It may make your arm sore for a few days, and it might cause a mild illness, but you cannot get the flu from it. It takes about two weeks for it to work completely, so if you happen to get the flu before then, it wasn't from the flu shot. (There's also going to be something available called a "live attenuated" version of the vaccine that you shoot up your nose. That's a little different, but is still hugely safer than getting the flu.)

The government is purchasing the vaccine and distributing it for free. There should be plenty of doses for everyone in the recommended groups, so there are no expected availability issues. Doctors and clinics can charge you an "administration fee", but that shouldn't be more than about $10, and I strongly suspect many places won't be charging it.

So please, even if you don't want a regular (seasonal) flu shot, find a way to get an H1N1 vaccine. The whole thing may very well turn out to be a bust, but this is truly a case where it is better to be safe than dead sorry.

Please pass this along to all your friends.

Looking forward to the rest of the fall Ultimate season.

Mother Hucker


At Sun Sep 20, 09:38:00 PM, Anonymous Anonymous said...

I am convinced. Can I get my regular flu shot and the Hinny (hee) shot at the same time?

I know how much you like stabbing me with needles, so when can I come in?

At Mon Sep 21, 01:05:00 AM, Blogger Rachel Cooper said...

This is brilliant.
Absolutely brilliant.

At Mon Sep 21, 01:18:00 AM, Blogger Unknown said...

Very informative and well written. One thing that I'd be curious about: If the current H1N1 virus were to mutate into a more virulent strain, what is the likelihood that the current H1N1 vaccine would interfere with the mutated version?


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