MMR and Autism Study (Farrington, Miller & Taylor, 2001)
- Vaccine Affect
- Sep 8
- 2 min read
C.Paddy Farrington, Elizabeth Miller, Brent Taylor,
MMR and autism: further evidence against a causal association
Vaccine,
Volume 19, Issue 27,
2001,
Pages 3632-3635,
ISSN 0264-410X,
This study set out to test whether the MMR vaccine could be linked to autism. The researchers looked at 357 children diagnosed with autism and compared the timing of their vaccinations with when their diagnosis was officially recorded. They expected that if the vaccine were a trigger, there would be a noticeable spike in autism cases shortly after children received MMR. Because they didn’t see such a spike, they concluded that MMR was not a cause of autism.
At first glance, this sounds like solid evidence — but when you look closely, the study has some serious gaps. First, autism is not diagnosed right away. In the 1990s, children were often diagnosed years after the first signs of autism appeared. This means that the “diagnosis date” the researchers used is not the same as the actual “onset of autism.” If the key period is around 18–24 months of age, when both MMR and first symptoms often occur, this study completely misses that connection by using much later diagnosis dates.
Second, the study doesn’t provide a clear breakdown of ages when children were first diagnosed or when symptoms began. Instead, it only gives a general overview, which makes it hard for others to check or challenge their findings. Without more detail, the claim that there is “no link” is based on very limited information.
Finally, the authors themselves admitted that there can be long delays between the start of symptoms and diagnosis, but they still dismissed the possibility of a connection in their final conclusion. In plain terms, their reasoning was: “We didn’t see a spike, so there must be no link.” But if you use the wrong measure (diagnosis dates instead of onset dates), you’re not really testing the question properly in the first place.
Conclusion
This study is often quoted as proof that MMR has nothing to do with autism, but its methods were too vague to rule anything out with confidence. It was a limited statistical exercise, not a definitive answer.
