Vaccines and the autism myth - part 1 The infamous Wakefield study kickstarted the Autism Myth, but many studies have since shown that there is no link between the MMR Vaccine and autism. Find out how it all got started. Rishi is a pediatric infectious disease physician and works at Khan Academy. These videos do not provide medical advice and are for informational purposes only. The videos are not intended to be a substitute for professional medical advice, diagnosis or treatment. Always seek the advice of a qualified health provider with any questions you may have regarding a medical condition. Never disregard professional medical advice or delay in seeking it because of something you have read or seen in any Khan Academy video.
Vaccines and the autism myth - part 1
- So for last 20, 30 years we've noticed an increased in autism.
- I'm actually gonna quickly scatch out a graph to show you what I mean.
- We have autism rates over here and if you fall them over time basically what
- happens that you see that things are going upwards. And the main reason that people say is awarness.
- They say we have more parents in families are aware of autism
- because we talk about it more nowdays.
- Then of course we're gonna bring it up with the doctors and it's gonna get diagnosed. And although that
- may be one reason for the increase, people have been searching for other reasons to explain
- the increase as well. In 1998 there was a team of doctors and researchers that put together a study,
- a study that we call the Wakefield study.
- It's named after the main author which was a guy named doctor Wakefield.
- He was a surgeon working in England.
- And in total there were 13 people, 13 authors on this study.
- So this study was done in United Kingdom and what they did
- was they took 12 children and these children came into the hospital
- reportedly kind of a normal way, the routine way that
- children come into the hospital. They were recruited and he found that they
- had developmental problems. So these were 12 children with some sort of developmental
- problem or delay and the most common example of a developmental problem
- among these kids was autism. So lot of these kids under the paving of diagnosis of autism.
- And what they did, I'm actually gonna scatch off for you.
- Let's imagine that this is the head of one of our children.
- What he asked them was you know do they have any symptoms,
- when did the symptoms start, all these kinds of things to kind of get it
- their history, their medical history. And lot of the families said you know we remember them
- having these symptoms of autism which I'm drawing as kind of a greyed out brain
- and there seems to be, this is their parents talking
- they felt like there's some sort of relationship with the vaccine.
- They felt like they remembered the vaccine specificaly the MMR vaccine - measles, mumps,
- rubella vaccine around the time that symptoms began
- and that's what he reported. So we actually have now a relationship based in turns of parents recolection
- between the vaccine and autism. But what the study was mainly about was actually the gut.
- So he was a surgeon and he wanted to look at the intestins of these kids.
- And he noticed that on the intestinal biopsies, when you actually got a little bit of
- tissue from these intestins, a lot of them had inflamation. That was what his
- paper was primarily about was this inflamation result.
- So he proposed and this is a big deal, he proposed that vaccine was causing this
- inflamation. He thought that was the cause of the inflamation and he then thought
- that perhaps there's some mystery protein, let's say this blue little protein, that
- maybe you take in through a diet, that can now because it's inflamed can get accros the gut
- and kind of affect the developing brain. So this was how he proposed there could be a link
- between the vaccine and autism. Now when the Wakefield study first came out in 1998 you can
- imagine the kind of excitement this created for lot of parents and families
- that have been for years looking for something to explain, why their kid had autism.
- And so finally people could kind of circle this and say ah! maybe was the vaccine that cause
- autism, that's what people thought. But there where couple of problems with this idea.
- The first problem was that some of the patients that had autism symptoms, they
- actually reported that they were having these symptoms before they had any of the
- gut symptoms. Now think about that, if you're having autism symptoms before
- gut symptoms not after, then that really goes against this theory because this theory
- is based on the idea that it's the gut that comes first, so immediately this is one
- concern kind of a big question mark over here whether this is really true.
- Another question mark is around this mystery protein up here. So this mystery
- protein, this is something that Wakefield never realy identified, he never said
- well I think it's this protein or that one, and in the last 15 plus years nobody
- has founded this mystery protein, that would explain what Wakefield was suggesting.
- So the fact, that nobody can actually find these proteins is also another big question mark.
- Neverthles a lot of studies started getting done. You know people started saying
- there truly is relationship between vaccines and autism. Then let's explore that further.
- So a group of studies were done around MMR vaccine rates. How often
- in a population do you actually see people getting them MMR vaccine. And you'd imagined
- that if there truly is a link between vaccine causing autism, if that's true
- then of course the vaccine rates must be going up, you know that would explain the
- autism going up. And so they actually looked in few different places and of course
- the first place to talk about is the UK, because of course the study was initially
- done in the UK. And in the UK they looked over 6 years and they found that actually
- MMR vaccine rates had been steady. There had not been in an increase. So already this is
- a little wierd if you're thinking that the vaccine is causing autism, you'd expect
- something different. So they looked again, actually looked another time. This time they
- actually looked in the US and in US they did the study over 15 years. And over 15 years same thing
- steady vaccine rates even though autism rates were going up. Now another study was
- actually done, this time in Canada. And surprisingly, in Canada turns out that the vaccine
- rates were actually going down slightly. So vaccine rates over 12 years now went down even though autism rates
- were going up. So this data is done at the population level, but it really does go against
- this idea that vaccine is causing autism. But people weren't satisfy with that. They wanted more
- specific research to be done on this mechanism that doctor Wakefield proposed.
- So another study was done and actually it was done in United Kingdom. And this study
- looked at 473 autistic children. So remember the initial study was done on 12 children and now
- we're looking at hundreds of children with autism. And among these 473 they actually wanted to
- figure out this part of the study, is there a link between vaccine and any sort of
- gut inflamation. And the answer was the resounding no there doesn't seem to be
- any relationship in autistic kids with vaccine MMR vaccine and inflamation of the gut.
- So that was actually very dodgemental to Wakefields theory. But what about this
- second part, this second link between gut inflamation and any sort of autism. This part right here.
- Well, again another study in the UK looking this time at 262 autistic children found
- that there is no link between these two things. So gut inflamation and autism did not seem to be related at all.
- So now the two important components of Wakefield's idea didn't seem to bear out.
- And then I should also just kind of cross this off this mystery protien bit because
- again people have been looking for that and no one seem to find that. But that wasn't
- good enoug because you get say well maybe there's still some link between vaccine and autism,
- but maybe this mechanism wasn't quite right. So research got done on this purple area over here.
- So they say: Ok, what about this. You know could it be possible there is a link between
- the two using some other mechanism. So study was done in the UK specifically looking at
- MMR vaccine and autism, is there a relationship and it turns out that they
- in this study looked at 71 autistic children and they found that among these children
- there was no relationship. And this study was actually you know way done again in fact
- in another setting, done in a different way but also tried to answer the same question of
- a link between vaccine and autism in Finland this time. They found that among
- 309 autistic children there was no link. Now remember this link that we created was
- done among 12 children and now we have hundreds and hundreds of kids in different
- countries and another one was done in the US and all these states were kind of finding
- the same result that basically there were no links that they could find between vaccine and
- autism. And so people started really doubting the truth behind the very first study,
- that first study done on 12 kids. But people were still talking about it and said you
- know what about that Wakefield study. Isn't it possible that there could still be a link
- in spite of all this other evidence. So finaly a group out of Finland tried to do another
- type of study with definite approach, but they found kind of conclusively answer the question. They basically
- said well fine, why don't we follow 1.8 million children, so this is many many children
- that were getting vaccinated and just follow them over time and see if they develop
- autism. And this might kind of answer once and for all whether there is a link.
- And so they followed these kids over time and they found a grand total of zero cases of vaccine
- associated autism. So in all these cases of vaccination none of them resulted in autism.
- So this point people really stop beliveing this study the Wakefield study and whether
- there was any link that was kind of resolve all these studies kind of said no
- there was really no link between vaccine and autism. But a question remained around the
- Wakefield study and how those results were found in the first place.
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