May 2010: VAERS maps and state population

This month I will look at map reports which both MedAlerts and CDC Wonder offer. The map shows the density of VAERS events that occur in each state. However, no matter what you ask, it always looks more-or-less the same, because the states with the highest population always have the largest number of VAERS events. Here are four different map views of VAERS data:

• Upper-left All VAERS data.
• Upper-right Only VAERS events that mention H1N1 Flu shots.
• Lower-left Only VAERS events that involve a child under 6 month of age.
• Lower-right Only VAERS events that report a life-threatening reaction.

This tells us very little: no matter what you ask, most reports happen in California, New York, Texas, and all of the other densely-populated states.

This is not news.

What is really needed is to adjust the map so that it accounts for the population and shows the proportion of people in each state who are affected. And of course, MedAlerts is able to do that.

To show an adjusted map that accounts for population, you must first check "Expert Mode" in the upper-right of the search form. This offers a new option under "Show Map" called "Adjust for Census". What it does is to take 2009 estimated state populations and adjust the results so that they describe per-capita proportions. When you do this, the above four maps look much different:

Suddenly California, Texas, and other large-population states look like safer places to live because the percentage of people who have these vaccine reactions is much lower. Now it seems that Alaska and North Dakota are high-risk states. In fact, northern states seem to have more VAERS events overall.

Why do the northern states have more VAERS events per person? Could this be related to the cold weather and the Flu? Let's find out.

Another feature of MedAlerts in "Expert Mode" is the ability to reverse a vaccine search so that, instead of looking for VAERS events with a given vaccine, it looks for VAERS events without a given vaccine. So under the vaccine choices, next to "Selected Vaccines", check "Excluded". Then choose the four Flu vaccines. The result is here:

The northern states still seem bad, in fact even worse with Flu reactions removed. So the suggestion that colder climates are somehow related to Flu shots is not true.

What else could explain this map? I looked at a number of factors, including per-capita income by state, health-care spending by state, and health facilities by state. One measure does match: the number of hospitals per person. But it matches in reverse. The map below, from the now-defunct statemaster.com website, shows the density of hospitals in each state, with dark green being the lowest, and yellow/orange being the highest.

What this data suggests is that as the number of hospitals per person grows, so does the chance of having a VAERS events. Of course, there are surely many other explanations, but it seems from this data, that you can be healthiest if you steer clear of hospitals.

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