Victus Spiritus


The Seasonal Sickness: Influenza

23 Sep 2009

With the official arrival of fall has come my first sore throat/cold of the season. Hooray Fall. What is it that causes us to be more susceptible to flus this time of year? It turns out that most viruses are unable to propagate in the summer heat although they do survive. I'd like to offer a few links to both inform you and help minimize your exposure to potential new illnesses.

First it's a good idea to understand the background of influenza, and wikipedia is a solid reference:

Second, my friend and boss Ralph always recommends getting a flu shot. There are many statistics for getting sick with and without the shot at the CDC and elsewhere, but the the specifics are highly correlated to your age group, and overall health. As the flu strain (genetic variation) that circulates through the population may differ from those in the vaccine or nasal shot the efficacy of the shot diminishes. In laboratory cases the shot prevents 70-90% infection for the strains in the vaccine. But in any given year it may only prevent 15-30% of the actual cases. Here's some info from the CDC on the efficacy of vaccines:

Google has done a great job of making information available to those interested with flutrends ( You can save the data locally and plot it.

When I'm up and about later I'll put together a chart showing vaccination percentage versus the Google flu trends, then you can decide for yourself if getting the nasal spray or vaccine is the right decision. From my initial reading, there are definite advantages to getting the shot for the very young and for folks in the 65+ age bracket.

[caption id="attachment_1653" align="alignnone" width="10" caption="Current Year 2009-2010"]Current Year 2009-2010[/caption]

[caption id="attachment_1654" align="alignnone" width="10" caption="Past Years"]Past Years[/caption]

See Google does a much nicer job of layering legends/axes, I'm new to their chart API.

United States flu activity from June to July:

Australia flu activity from January to December:

New Zealand flu activity from January to December:

Mexico flu activity from July to June: