Analysis of Anti-Vax Graphs

by Robert Webb
This article also available (and nicer-looking) on the VecSkeptics website.

The anti-vaccine movement sometimes presents graphs to support their cause, supposedly to show that diseases were on the decline before vaccines came along, and that vaccines had no effect. Graphs seem hard to argue with. They look scientific, represent actual data, and are compelling to many people. And indeed a good graph should be compelling. But their graphs are not good. Let's have a look at how the true data, which supports the fact that vaccines have had a huge positive effect, can be manipulated to manufacture the conclusion the anti-vax movement wants.

Death rates

Firstly, most of the graphs they show are of death rates, not infection rates. Yes, death rates dropped significantly before vaccines were introduced because other improvements in medicine and sanitation meant that we were better at treating the disease, but it does not indicate that less people had the disease to begin with.

They also tend to show graphs going back a long time to when death rates for common diseases like measles were very high. To fit these high figures on the graph it's necessary to scale down all the figures, meaning that by the time the vaccine is introduced you can no longer see any drop it may have caused in deaths.

They never show graphs of death rates from third world countries where due to poor sanitation etc. death rates for diseases like measles can still be quite high.

Here's a nice graph though showing both infection and death rates in the US and it's clear from both that the 1963 vaccine had a huge effect.


Source: http://www.iayork.com/MysteryRays/2009/09/02/measles-deaths-pre-vaccine/

The anti-vaxxers claim (e.g. here) that death rates are more reliable than infection rates because they don't trust the diagnoses made by doctors. The idea is that doctors are biased against diagnosing a disease if the patient has been vaccinated against it. But if the symptoms match, why wouldn't they test for it? We all know that vaccines are not 100% effective. The above graph shows that infection and death rates are very closely matched, year by year, so it seems that the doctors' diagnoses match the coronors' reports, so where's the evidence for this supposed misdiagnosis?

Infection rates

So the best way to see if a vaccine worked is to look at infection rates. I've only seen one infection graph presented by the anti-vax side (in several places, but I found it on the AVN website), so let's look at that in some detail. Here it is:

This graph has already been demolished on Science-Based Medicine, so I'll try not to repeat too much of that, though I need to recap a little. Mostly I want to show some new graphs (in the next section) that help explain what Dr. Raymond Obomsawin did to create his graph, and how easily his techniques can be used to get any result you want.

Dr. Obomsawin gives this link as his source for the graph. Here's the original graph:
[Update: the PHAC has since updated their graph and fixed the error of the phantom 1959 data point which I mention below. Follow the link above to see their updated graph]

But a better graph of the same data, where actual data points are shown, can be seen here:

So what's wrong with the graph?

Here's some (but not all) of the ways that this graph deceives us. Looking at the original graph, it's quite obvious the effect the vaccine had. To take this data and manipulate it to give the exact opposite impression is clearly intellectually dishonest. It's hard to believe Dr. Obomsawin would not be aware of this deception, though it's conceivable that he sees himself as "finding the truth" within the data. Who knows.

Update: Dr. Obomsawin continues to mislead the public regarding vaccines, and continues to use the graph discussed above, as you can see in this 2012 video at the 44:50 mark. They have disabled comments of course, but you can still show your dislike for it. I did post a reply on their YouTube discussion board too which you're welcome to vote up!

* See also my Herd Immunity Simulator.