Flu update

Continuing my series from WhiteCoat Underground, here is the latest influenza update.

While still widespread, numbers are finally starting to drop. I'm ready to drop myself. It's been a terrible season---the worst I've ever seen. This is probably due, at least in part, to this year's flu vaccine missing some unanticipated strains.

For those of you out there who don't "believe in" flu shots, remember that vaccination isn't a religion. The anti-vaccination forces are, however, rather cult-like. Here's some info for you.

Influenza is a serious illness, and vaccination can prevent or reduce severity of illness. Partly as a response to some anti-vaccine nuttery, I think we should talk about this a little bit. But just a little. There is plenty of information available elsewhere. But at least a little summary.

Influenza is primarily a respiratory illness. When I see it in the clinic, it's often fairly obvious...high fevers, muscle pain, dry cough, cold symptoms. It's very unpleasant, at least for most people. For some, it's deadly. Now, I'm not talking about "bird flu" or any other exotic disease. I'm talking about the "regular" flu that sweeps the globe yearly. In the North America, this happens in the winter, and death rates rise. Most flu deaths are due to either a severe case of influenza itself (as was probably the case during the 1918 pandemic) or because of complications, primarily pneumonia--the damaged lungs of flu victims are particularly susceptible to pneumonia.

Last month, a patient said to me, "Now, this will make sure I don't get any flu or colds, right?"

"Um, no...this will help prevent you from getting some flus, and if you do get it, it will help prevent you from dying of it. It won't do a thing for your colds."

Everyone asks me if it will give them the flu, and the answer is a resounding "No!" It does cause your immune system to make antibodies to the flu virus, but it doesn't give you any diseases. We give flu shots during cold and flu season...I can almost guarantee you will get sick at some point after the shot---but that isn't in any way related to your vaccine.
But flu shots do the job they are supposed to do pretty well. The complex, global process of developing flu vaccines works. The New England Journal of Medicine just released a well-done study on the effect of flu shots on the elderly--the results are dramatic.

There is much written in the conspiracy-oriented corners of the blogosphere about the supposed ineffectiveness, danger, and God knows what else bad about flu shots.

It's all bullshit.

There are legitimate questions to be asked about influenza vaccinations, about public health priorities, but these discussions should be based on data.

Statistics

Data is one of the points of contention among some of the conspiracy theorists. They loudly denounce the CDCs figures on flu mortality.

The CDC reports what is calls mortality due to pneumonia + influenza. This confuses people. It confused me. How do we know how many people are dying of influenza if the stats are mixed with pneumonia?

The answer is complicated--science is hard. That bothers some people--they think science should always be intuitive. Sorry.

A pretty complicated statistical analysis is applied to the available data. Since most cases of influenza aren't actually tested, a certain amount of mathematical modeling must be used. (See BMJ 2006;332: 177-178 (21 January), and American Journal of Epidemiology 2006; 12:344-52.). These models have proven very successful. They make for boring reading, but I encourage you to give it a try.

Some would argue that excess winter deaths are simply "culling the herd". If they wish to have that discussion, good luck, just don't debate my mom...you'll lose.

The bottom line is that flu shots save days lost from work, days of misery, and most of all they save lives. Get one every fall---thank me later.