I’ve generally steered clear of this debate (at least in print), but this study is so significant that I can’t resist.
Those who’ve followed the MMR-autism issue will be aware of the continuing insistence from some segments of society that childhood vaccines are implicated in the development of autism. This has been the case for over twenty years now. Despite continuing evidence to the contrary, some elements remain very vocal, largely based on their own personal (and no doubt sad) personal experience. This has had alarming consequences in some parts of the world of decreasing levels of vaccinations against preventable diseases. In some areas of some countries, including the US and Australia, vaccination rates are close to, or have dropped below, the threshold for ‘herd immunity’. When herd immunity exists, individual infections do not result in a runaway epidemic. The opposite state is clearly undesirable.
The Institute of Medicine (IOM) is the non-profit organisation which was asked to carry out this study on behalf of a US government department. Here also is a nice overview. The were requested to review a list of adverse events associated with 8 different vaccines, to determine whether there’s a causal link or not. That is, did the vaccine cause the adverse event or not.
Note that they weren’t asked to evaluated the effectiveness of the vaccine, only the probability of an adverse event being caused by it.
Using existing epidemiological evidence, the IOM proceed to assign vaccine-adverse event pairs to one of four categories:
- Evidence convincingly supports a causal relationship
- Evidence favors acceptance of a causal relationship
- Evidence favors rejection of a causal relationship
- Evidence is inadequate to accept or reject a causal relationship
The bottom line? While the MMR vaccine is implicated in a range of adverse events like fever and joint pain, the study found that the evidence favours rejection of any causal relationship between MMR vaccine and autism or diabetes.
While it’s always prudent to be vigilant about these things, I believe that after decades of review, the evidence continues to be clear that, while not totally devoid of risks, vaccines are generally safe and a boon to society.
It’s just a pity that the likes of Meryl Dorey and the deceptively named Australian Vaccination Network are working tirelessly to undermine this valuable and ingenious human development in the name of their misguided philosophy.