Good science vs outspoken parents

PBS’s Frontline had a very good documentary this week, discussing the dispute that has raged for the last 12 years or so regarding the safety of vaccination, particularly with regard to the misguided belief of some people that autism can be caused by adverse reaction to the vaccines.  I commend Frontline for staying on the side of real science, and not the witch-hunting fears of those who think temporal correlation means causation…

Many people who are dealing with children who exhibit development problems are looking for someone to blame.  The fact that they began to see symptoms in their children after vaccination is an interesting correlation, but correlation does not equal causation.  That is why so many studies have been done looking at the relationship between the MMR vaccine and autism, or thimerasol and autism.  But the studies have found no correlation, let alone causation.  Failure to find correlation means it is EXTREMELY unlikely that there is any relationship at all.  And without correlation, causation is nigh impossible to find – especially if you have no idea what the causation pathway might be.

The problem here is that the general public do not have sufficient understanding of the scientific method or statistics.  It is easy to see relationships, even where none exist – that is a human cognitive feature.  And when we are dealing with a single case (anecdote), many people fail to realize that this CANNOT show causation, without a lot more information of exactly how that cause/effect relationship is organized.  It is IMPOSSIBLE for medical science to prove beyond all doubt that a vaccine or drug is safe – but they can show that the benefits outweigh the risks.   Prior to the introduction of the measles vaccine in the US in the 1960s, hundreds of thousands of cases PER YEAR were reported, and the death rate was often in the hundreds.  Considering no scientific study has shown vaccines to have a such significant downside, we must side with real science and accept vaccination as a safe technology.

So please, have your children vaccinated – the need for herd immunity is great.

And remember, the only way we can ever discontinue a vaccine is if we eradicated the disease from the human population – as was done with smallpox in the 1970s.  We should have eradicated measles and polio by now, but fear-mongering has scared too many people away from vaccines, both in the developed world (in the case of measles) and the developing world (see Nigeria).