Science can prove a negative---
20 March 2005
Lawyer, graduate physicist, former examining Univerisity lecturer in law
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Re: Science can prove a negative
SCIENCE CAN PROVE A NEGATIVE
What Mr Jacobs says (1) could mislead my fellow lawyer Ian Barnett (2).
Regrettably, and with my respects to him, but Mr Jacobs has got it wrong yet
again. He claims 'in medical research, you can never prove a negative'.
If scientific method is applied to medical research, science can prove a
negative in more than one way.
We can also establish that MMR vaccine causes autism, and that has been done
(3). Therein lies the problem for the pro-MMR camp and why they fall back on
regrettably inaccurate epidemiology which proves nothing, as Mr Jacobs so
readily agrees (1):-
is indeed no evidence that proves there is no link between MMR and autism.'
What has been produced so far is so inaccurate that it is shameful and that is
before taking into consideration all of the detailed criticisms of the papers
produced, which criticisms can be read elsewhere.
Standard procedures for the assessment of adverse drug reactions are well
established and applied worldwide (except by our government when it comes to the
MMR Children). Government, pharmaceutical companies and the medical professional
hierarchy will not accept that evidence, despite it being obtained by the
application of their own well-established standard procedures and science which
they also refuse to apply. 'Dechallenge' and 'Rechallenge' are significant parts
of those procedures and science.
Mr Barnett will easily understand what powerful evidence of causation a
'dechallenge' case series is if he considers by analogy the famous case of R v
Smith, better known to the public as 'The Brides in the Bath' case (4). R v
Smith is one of the leading cases on similar fact evidence and is applicable by
very close analogy to a 'dechallenge' case series. What is particularly striking
is that proof by dechallenge requires only three well documented cases of
positive dechallenge. What is also striking is the high standard of proof it
affords. Similar fact evidence is proof beyond reasonable doubt, so this will
demonstrate to the non-scientist why dechallenge is so powerful.
'Dechallenge' sounds fancy but its essence is simple if we strip away the
embellishments. The drug is administered (challenge). The subject suffers a
reaction. The drug is no longer administered - the subject recovers. With only
three well documented cases of positive dechallenge, causation can be
established. A simple search through numerous medical journals will show this is
well-known in pharmacological research, but it is sometimes not so well-known to
More interestingly, whilst dechallenge is powerful in its own right, an even
more powerful proof of causation is positive well documented rechallenge. Only
one case of positive rechallenge establishes causation. Rechallenge is where the
drug is readministered and the subject suffers the reaction again. Rechallenge
was not a feature of R v Smith. It is not a simple matter nor was it necessary,
after having succeeded, to murder the same person twice.
In the ‘brides in the bath’ case, the defendant was
accused of one murder but evidence was offered of two more. The admission of
this evidence followed similarly from the improbability that three different
women with whom he had gone through a form of marriage, and who had made
financial arrangements from which he would benefit, had all drowned in the bath
by accident shortly afterwards.
There was no direct evidence the accused committed the murder charged, but
similar fact evidence proved it causally to the high criminal standard
of proof. Similar fact evidence is evidence of such similar and
unique prior behaviour of the accused, that it is proof of guilt of the accused
beyond reasonable doubt. This is exactly the same with MMR
where no one has seen the 'murder' being committed by MMR but whilst everyone is
trying to find the murder weapon in MMR's 'hands', dechallenge and rechallenge
is the scientific pharmacological equivalent of 'similar fact evidence' as proof
of causation and notably, the criminal standard of proof 'beyond
reasonable doubt' is analogous to the very high scientific standard.
Notably, in the brides in the bath case, not unsurprisingly, there was no
rechallenge (ie. 'brides in the bath' was dechallenge only) and it is not
strictly dechallenge because it is impossible to 'undrown' the brides in the
cases in question. However, we do know that anyone can recover from drowning if
rescued and resuccitated in time, so it is not essential in this particular
example - we know full recovery was possible. Further, there were three
examples just like a dechallenge case series which requires only
three well documented case histories to prove an adverse event was an adverse
'similar fact evidence' is an exception to the rule that such evidence cannot
normally be adduced in a criminal trial. It is not evidence that is directed to
proving the specific offence charged. It relates to other offences beyond the
scope of the trial. Hence it is normally excluded as it would have a prejudicial
effect that outweighs it probative value for the specific offence charged. In Mr
Jacobs' example, it would not normally be relevant to prove he committed this
particular burglary that he had committed 20 prior burglaries but it would most
likely be prejudical to a fair trial and outcome.
So, what did happen when a rechallenge case series was presented to the
Andrew Wakefield presented a case series in 2001 to the IoM Immunisation Safety
Review Committee. He is quoted (5) relating:-
they became anxious and agitated. They then asked for the data to be
provided to their closed session the following day. .... Yet they didn’t
mention the relevant parts of any of my testimony or data in the final
...... I raised this
issue at the second congressional hearing on autism and vaccines in front of
Marie McCormack, Chair of the Institute of Medicine’s Immunization Safety
Review Committee. Representative Dan Burton told Dr. McCormack that they
needed the transcript from that closed session. She explained that it was
not their policy to release transcripts. He said in his own idiosyncratic
style that they would then be subpoenaed, though he put it more forcefully
than that. So, they were subpoenaed and the tapes were sent.
They just happened to be blank. These were
copies of the original tapes, so Representative Burton said, “Okay, then in
that case we will have the original tapes.” So they requested the original
tapes—and they were blank as well."
As for Mr Jacobs further points, these are argument without substantiation and
substance. I would suggest that others might wish to post weblinks to the
commentaries which pull to pieces the epidemiology so that Mr Barnett and any
other interested parties can read them and see how flawed the government
Mr Jacobs had a go himself at defending the Madsen paper, when even Madsen did
not bother (no doubt Madsen realising it is a completely lost cause, but not
before grabbing the headlines first). Mr Jacobs' points, the sole defence of
Madsen appearing the Journal of American Physicians and Surgeons late last year,
did not survive criticism, sad to say. They ended up the same way as did the
paper he was attempting to defend. That's statistics for you - its all a game of
Email: bmj050319"replace 'at' sign"millercompany.demon.co.uk
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Reply Re: Simply a concerned parent 19 March 2005
a concerned parent 18 March 2005
3) See text to footnote 5)
4) R v Smith, 1915, (11 Cr App R, 229)
5) P.7 ‘Autism and the MMR Vaccine - An interview with Andrew Wakefield, MD’ -
Fall 2001 -
Competing interests: Close relative with life threatening food allergy