August 4, 2004

Epidemiologic Evidence Is Insufficient To Prove There Is No Link Between The MMR Vaccine And Autism

By Clifford G. Miller

This is an important point concerning the inappropriate use of epidemiologic 'evidence' cited to support the 'No Vaccine Causal Link To Autism' proposition. 

The source of the following is the main US judicial work of reference on scientific evidence which is also used as a training manual for US judges.

Just so that this is clear to all, the US Federal Judicial Centre Reference Manual on Scientific Evidence, Second Edition, makes abundantly clear that epidemiology is not acceptable to prove there is no causal link between an adverse event and a pharmaceutical .  I quote from the Epidemiology Chapter, page 381 (emphasis added)

"Epidemiology is concerned with the incidence of disease in populations and does not address the question of the cause of an individualís disease. This question, sometimes referred to as specific causation, is beyond the domain of the science of epidemiology. Epidemiology has its limits at the point where an inference is made that the relationship between an agent and a disease is causal (general causation) and where the magnitude of excess risk attributed to the agent has been determined; that is, epidemiology addresses whether an agent can cause a disease , not whether an agent did cause a specific plaintiff ís disease ."

Please note this is stated by reference to the injured Plaintiff seeking to prove the cause was the drug company's product.  Epidemiology papers appear to be relied on heavily as the science for the proposition that, 'there is no link between MMR and autism'.  The Reference Manual on Scientific Evidence specifically rules out epidemiology as proof of specific causation, stating that it can only go to prove that an agent could have caused but not that, in any particular case, it did cause. Hence, the oft repeated citing of epidemiology as proof of the opposite , that there is no causal link, is more than a little incongruous and a somewhat bizarre scientific base on which to put any nation's policy on immunisation of children . The logical implication seems to be that epidemiology can never be used to prove that a particular agent did not cause a particular adverse event.  All that epidemiology could possibly be considered to prove is that the likelihood the adverse event was caused by a particular agent is small, and not that there is no likelihood

An electronic version of the Reference Manual can be downloaded from the Federal Judicial Centerís website.

Editorial note: The author is an English lawyer, admitted to practice English law in England and Wales. This editorial is meant to provoke discussion and anyone in the U.S. who wishes personal advice on this issue should seek the independent views of a qualified U.S. attorney.

The author is also a graduate physicist of The Imperial College of Science Technology & Medicine (London University) and sometime lecturer on law (notably  evidence) standards and ethics at The Imperial College.