June 2010: Autism and VAERS data

Autism is an epidemic. Time Magazine reports that 1 in 100 children are autistic. A parent survey claims that it appears in 1 out of 91 children and that boys are four times as likely to be autistic.

Although medical professionals deny that there is a link between vaccination and autism, many parents feel otherwise (see here or here). They often blame the MMR vaccine. Are they correct?

Let’s ask MedAlerts which VAERS events list autism as a symptom, and which vaccines were given to those people.

The first question is which VAERS events have autism as a symptom. This can be asked in two ways, both in Section 2 of the search form:

  • Symptoms. We can search for autism symptoms. To do this, it is helpful to understand the MedDRA symptom classification, which organizes all known symptoms at five levels of detail. MedAlerts normally shows only the lowest level of the symptom classification in the “Symptom Keywords” list. However, in “Expert Mode” (obtained by checking the box in the upper-right of the search form) it is possible to look at any level of the symptom classification. Autism is a collection of low-level symptoms, so it is easier to look one level higher (the “PT” level) for these symptoms. To do this, check “Expert Mode”, choose “PT” under the Symptom list, and then select two entries: “Autism (10003805)” and “Autism spectrum disorder (10060974)”.
  • Write-up. We can search for the word “autism” in the event write-up. This is certainly easier to do: just type “autism” into the “Write-up” search field. Of course this is less accurate because the word may be mentioned in cases where autism is not really indicated, and also it may be omitted in cases where the symptom does exist.

Once the symptom is selected, use Section 1 of the search form to request a Table of “Vaccines”. This will give a list of every vaccine associated with an event that lists the autism symptom. Click on the green down-arrow at the top of the table to sort it by the number of events.

What do we see?

If the search is for actual symptoms, 2230 events are found, and the top vaccines (those that account for more than 10% of the results) are shown here.
Searching Symptoms
Vaccine Events Percent
MMR 1437 64.44%
HIBV 446 20.00%
DTAP 353 15.83%
HEP 338 15.16%


If the search is for the “autism” keyword in the write-up, 1862 events are found, and the top vaccines are shown here.
Searching Write-up
Vaccine Events Percent
MMR 1170 62.84%
HIBV 360 19.33%
DTAP 301 16.17%
HEP 267 14.34%

So no matter how you search, the result is the same. The MMR vaccine has been given to nearly two-thirds of all people who subsequently report an autism-related VAERS events. No other vaccine comes close to showing such a strong link.