In response to
BMJ  2004;328:602 (13 March), doi:10.1136/bmj.328.7440.602-c
News roundup
Authors reject interpretation linking autism and MMR vaccine

AND in response to
 Clifford G. Miller,
Solicitor & graduate physicist

F. Edward Yazbak,
Pediatrician, Director,
TL Autism Research, Falmouth, Massachusetts 02540
Send response to journal:

Email F. Edward Yazbak

 The Tragic Second Hit.

As quoted by Mr. Clifford G. Miller, my statement was 'Some parents have
also reported that their children, after improving on special diets,
supplements and behavioral therapy, regressed a second time around the age
of 5 years shortly after receiving their MMR booster. Such double-hit
situation (challenge-rechallenge) has been accepted in courts and by a
committee of the Institute of Medicine (IOM) as proof of causation'. (1)
Mr. Miller has interpreted the above as implying that the IOM and US Courts
accept evidence showing a double reaction, first to the initial MMR
inoculation and again to the MMR booster, as proof of causation. When Mr.
Miller contacted me, I informed him that my reference to the IOM was about
another vaccine and that the Court litigations involved certain medications
and not the MMR vaccine. His legal interpretation of the situation is
nevertheless still valid, and on target, when he states ". it seems a
logical and possible premise for a court to follow on a balance of
probability in the absence of any other cogent and persuasive proof of
causation. If that is the case, then this debate was over long ago and that
also means it may have been prolonged unnecessarily by whatever interests
there are that have been using science in a manner in which it is not
intended. This may well have again have caused damage to the reputation of
science in the public mind, when it can be such a powerful tool for good."

My reference to the IOM is based on two documents. The first is a 1991 IOM
report entitled "Adverse Effects of Pertussis and Rubella Vaccines" and
edited by Howson, Howe and Fineberg. On page 48 the editors stated: "In the
case of hemolytic anemia, a single striking case was sufficient to suggest
biologic relevance" and under Summary on page 159: ". the case described by
Coulter and Fisher (1985) is suggestive of a causal relation because
hemolytic anemia was detected 6 days after DPT immunization on two separate
occasions". The second IOM report "Adverse Events Associated with Childhood
Vaccines: Evidence Bearing on Causality": was published in 1994 and was
edited by Stratton, Howe and Johnston. On page 24, the editors listed
several criteria including .6. Dechallenge: Did the adverse event diminish
as would be expected if the vaccine caused the event ... 7. Rechallenge:
Was the vaccine redministered? If so, did the adverse event recur? On page
26 they added "Rechallenge is unusual, because physicians are unlikely to
readminister a vaccine previously associated with an adverse event. When
rechallenge does occur, however, the recurrence or non recurrence of the
adverse event will often have a major impact on the causality assessment".
The above references should be available from the IOM. (2)

As mentioned, the principle of Challenge and Re-Challenge has also been
cited, in several Court proceedings involving Selective Serotonin Reuptake
Inhibitor (SSRI) litigation. Interested attorneys can obtain those
transcripts by simple Lexus-Nexus and Google searches. As for physicians,
the following three documents may be more informative. The first is a
comprehensive Power Point presentation on "Clinical Analysis of Adverse
Drug Reactions" by K. A. Calis, Pharm.D., MPH, of the National Institutes
of Health. (3) Under "Causality Assessment" on slide 38, Dr. Calis lists
De-Challenge and Re-Challenge after temporal relationship and before
dose-response relationship. On slide 45, under "Component of an ADR
(Adverse Drug Reaction) Report", Dr. Calis once more lists "De-Challenge
and Re-Challenge information".

The second article is by Ms. Vera Hassner Sharav, President of The Alliance
for Human Research Protection (AHRP) in New York. It is entitled "Where is
the Scientific Evidence to Justify Exposing Children to the Risks of
Antidepressant Drugs?" (4) and was submitted to the FDA
Psychopharmacological Drugs Advisory Committee. The author states:"The case
is particularly significant in demonstrating a causal effect of the drug
because: It occurred within the context of a controlled clinical trial;
Violent symptoms developed with start of "Drug" (challenge); The symptoms
ceased when the drug was stopped (dechalllenge); Suicidal symptoms returned
when the drug was restarted (rechallenge); Suicidal symptoms cleared a
second time when the drug was again stopped".

The last reference, "Suicide and Neuropsychiatric Adverse Effects of SSRI
Medications: Methodological Issues" by Ronald Wm. Maris, PH.D, Professor
Emeritus, University of South Carolina, was read at a symposium in
Philadelphia on October 4, 2002. (5) Dr. Maris stated:
"Challenge/Dechallenge/Rechallenge studies are a useful and reliable
methodology in suggesting drug or SSRI drug causation. In a
challenge/dechallenge/rechallenge study patients or subjects are given
specific ADs /SSRIs (See Rothchild & Locke, 1991; King, Riddle, Chappell et
al., 1991; Beasley rechallenge protocol for Lilly, 1991). If an adverse
reaction occurs, the drug may then be discontinued. The adverse side-effect
may also stop. Finally, the AD drug may then be readministered and the
adverse side-effect may reoccur. Other things being equal, it is
scientifically sound to posit in such circumstances that this drug was a
proximate cause of the adverse side-effect (See Grounds et al., 1995;
Teicher et al., 1990; Mann, 2000: 100)."

Many families, including our own, have seen and documented regressions
after the first MMR vaccination and then again after the booster. Even if
the parents were lured into believing that the initial regression was "just
a coincidence", no one can convince them or for that matter convince a
Judge or Jury, that a profound second regression, after a period of
improvement, is still yet another coincidence. The tragedy of this
situation is that 92 to 95% of children develop immunity to all three
diseases after receiving their initial MMR.


1. Regressive Autism and MMR Vaccination F. Edward Yazbak, MD, FAAP, TL
Autism Research.

2. The Institute of Medicine of The National Academies 500 Fifth Street NW,
Washington DC 20001 E-Mail: Website: Tel:
202.334.2352 .Fax: 202.334.1412

3. 2003.ppt

4. ttp://


Competing interests: Grandfather of a boy with two documented regressions,
autistic enterocolitis and evidence of Measles Genomic RNA.