fourteen studies


Quick History

The Right Question

The "14" Studies

Studies Ranked

Our Studies

Good Guys, Bad Guys

Now What?


About Us Study Analysis

"Pervasive Developmental Disorders in Montreal, Quebec, Canada: Prevalence and Links With Immunizations"
Pediatrics, Eric Fombonne, MD (July 2006)


The worst MMR study ever done? We think so. Used a statistical trick by using MMR uptake data from one city (Quebec City) and comparing it to autism rates in a different city (Montreal). No surprise that it was published in Pediatrics. Study author, Fombonne, is one of the most conflicted researchers we have seen.

Actual Question This Study Asked & Answered:

Q: Are MMR uptake and PDD rates related in Montreal?

A: No

Did the study look at unvaccinated children?

A: No

Conflict of Interest:

"In the United Kingdom, Dr Fombonne has provided advice on the epidemiology and clinical aspects of autism to scientists advising parents, to vaccine manufacturers, and to several government committees between 1998 and 2001. Since June 2004, Dr Fombonne has been an expert witness for vaccine manufacturers in US thimerosal litigation."

Ability to Generalize:

Hard to generalize when you use corrupt data.

Post-Publication Criticism:

High due to poor methodology.

Scoring (Out of 40 possible points):

Asked the Right Question:0

Ability to Generalize: 0

Conflict of Interest: -1

Post-Publication Criticism: -1

Total Score: -2

Guest Critic #1: Dr. David Ayoub

Fombonne’s errors keep vaccine-PDD hypothesis alive in Quebec

By David M. Ayoub, MD

In their article published in the July 2006 issue of PEDIATRICS, Fombonne et al concluded they "clearly failed to detect" an association between either Thimerosal exposure or MMR vaccine uptake and pervasive developmental disorders (PDD) rates in Montreal. (1) We strongly believe their failure to detect such an association was related to methodology and design flaws and that they have not adequately demonstrated that a vaccine link can be dismissed.

Fombonne et al evaluated children enrolled in only one of Montreal’s five school boards in an attempt to estimate the prevalence of PDD in Montreal. The authors appropriately cautioned that PDD rates in Lester B. Pearson School Board (LBPSB) may not have been representative of rates elsewhere and suggested that data from other school boards should be assessed but claimed, "this information was not available in the survey data that we could obtain."

One of us (MR) easily obtained this data of all five Montreal school boards from the Ministry of Education of Quebec (MEQ). Our analysis indicates that the enrollment at LBPSB in 2003-04 represented only 14% of all total school board enrollments in Montreal. More unusual, the PDD rates at LBPSB were significantly higher than the other four school boards, separately or combined. In some matched birth cohorts the prevalence of PDD was as much as three times higher among LBPSB students. Therefore, Fombonne’s objective to calculate the PDD prevalence in Montreal could not possibly have been accurately estimated by assessment of this particular school board and any conclusions about a relationship between vaccines and PDD rates in Montreal could be seriously flawed.

The authors committed a serious selection bias by choosing to study only a small subset of the children in Montreal’s schools. PDD rates at LBPSB, a Center of Excellence in Autism, are likely influenced by the fact that it is the only totally inclusive school board of the Province and that it has a very high ratio of integration of students with PDD into regular classes. Therefore, many families of children with PDD often seek to enroll their children in LBPSB resulting in an overestimate of true PDD rates in Montreal.

The English-speaking LBPSB is a poor representation of the general Montreal student population whose mother tongue is most commonly French (43%), followed by various non-English languages (37%) and lastly English (22%). (2) Montreal, the second largest French-speaking city in the Western hemisphere, attracts many immigrants. Quebec’s language law Bill 101 which protects the French-language restricts access to immigrants and French-speakers to English schools. Only children of parents having done most of their elementary studies in English can attend English schools. Most French-Canadians and children of immigrants who are a majority in Montreal are forced to attend French schools. Consequently, the LPBSB and other English school boards do not represent Montreal’s true ethnic diversity. In 2004, only 25.9% of Montreal’s student population attended English schools such as LBPSB. (3)

Fombonne et al erroneously stated that Thimerosal-exposure after 1996 was "nil" but analysis of numerous Canadian government healthcare documents suggests otherwise. According to the Public Health Agency of Canada thirty-three licensed vaccines were still in use as of March 2003. (4) Some Thimerosal-containing vaccines, including those against hepatitis B, influenza and meningococcus specifically target infants and early childhood. Since 1994 the majority of 4th grade students participated in an elective Hepatitis B vaccination program, but the first Thimerosal-free hepatitis B vaccine was not licensed in Canada until March 2001, providing more evidence that Fombonne’s study population was exposed to Thimerosal. (5,6) A fully Hepatitis B-vaccinated child could have received 37.5 micrograms of mercury or more by six months of age prior to availability of preservative-free vaccine and within the study period that Fombonne characterized as "nil" mercury exposure. In addition, the reconstituted Penta vaccine available in 1997 still contained 25 micrograms of mercury per dose and could have resulted in an additional 100 micrograms of cumulative mercury exposure in children vaccinated at 2, 4 and 6 and 18 months of age. (7)

Fombonne failed to consider that immunization schedules varied in Montreal resulting in more mercury exposure in some groups than others. According to the Protocole d’Immunisation du Québec foreign-born children and native children less than 7 years old with at least one parent who has emigrated from areas with a high prevalence of Hepatitis B (over 100 countries) must receive the Hepatitis B vaccine series. (8) Meningococcal vaccines, some with Thimerosal, had also been administered more frequently to these groups. More importantly, immigrant children without adequate vaccine records are required to repeat the complete Canadian immunization schedule, further increasing their cumulative exposures. (9)

Regarding internationally adopted children, Sandra Caron, clinical nurse of the International Health Clinic of Ste. Justine's children Hospital, Montreal wrote: "Practically all children present a vaccinal delay or don't have the same vaccines than here, or vaccines of foreign countries are more or less reliable, so vaccination has to be readministered from the beginning."(10) These children therefore represent yet another unique subset of the population that could have been exposed to even larger amounts of Thimerosal during Fombonnes's "nil" exposure period.

Fombonne et al claim that the vaccine records of the 180 children with PDD were not available, but this seems odd since they claim 80% of the children with PDD had been seen in their own institution. We have obtained several vaccine records from Quebec parents confirming Thimerosal exposure after 1996. For example, the son of one of us (MR), who was adopted from abroad and entered Canada at three months of age, received over 100 micrograms of mercury between October 1997 and March 1998 by the age of six months. It is likely other children in the post-1996 birth cohorts also received Thimerosal.

Because foreign-born children and children of immigrants likely have greater Thimerosal exposures, we performed our own subgroup analysis of PDD at LBPSB in 2003-04 and discovered a rate of 106.6 per 10,000 in foreign-born children vs. 67.6 among natives. PDD rates were also significantly higher among LBPSB children with one or more immigrant parents. Numerous reports of higher PDD rates among immigrants have been reported in Canada and other industrialized countries. A more extensive assessment is clearly warranted.

We must also protest the manner in which Dr. Fombonne evaluated changes in PDD prevalence following adjustments in the cumulative Thimerosal exposure yet applied an entirely different standard when defining cumulative MMR exposure within the same population. A cumulative exposure is typically calculated by multiplying three independent variables: dose per vaccine, shot frequency and coverage rates for each vaccine. Dr Fombonne defined cumulative Thimerosal exposure by considering only the amount in each vaccine and vaccine frequency but ignored coverage rates. He applied the opposite standard to the MMR exposures and only considered coverage rates. Thus, he ignored the fact that autism rates increased following a doubling of the MMR exposure after 1996 when a second MMR shot was added to the immunization schedule and chose to emphasize that a rise in PDD rates coincided with a decline in MMR coverage rates. Obviously the increased amount of administered viral load to the population was far greater influenced by a doubling of shots administered than by a marginal drop in immunization coverage rates. He likewise ignored the potential impact of mass measles immunization campaigns in Quebec that delivered a second dose of measles to a large number of infants and children throughout 1996. (11) The subsequent rise in PDD shortly after that campaign is clearly depicted in their figures and would lead us to believe this observation supports an association between PDD and MMR exposure.

Finally the paper’s observation about rising PDD rates seems to contradict Dr. Fombonne’s well-known contention of the lack of evidence of an autism epidemic. In an Inserm interview, Dr. Fombonne said, "to declare an epidemic, or sensible increase of the prevalence, it would take incidence studies, always the same, year after year, but this data is not available in any country." (12) The database we obtained from the MEQ represents the type of dataset Fombonne stated was required to detect true increases in PDD. According to one Montreal-based autism organization, data from the MEQ revealed an increase in annual PDD cases in Quebec from 410 (1990-1991) to 4,483 (2005-2006), a nearly 1,000% increase over 15 years. (13) This is staggering and is strong evidence of a real rise in neurodevelopmental illnesses that cannot possibly be solely genetic in nature but supports an environmental etiology.

In conclusion, the numerous flaws in the Fombonne et al study along with the lack of confirmation of non-Thimerosal exposure in their PDD cases renders the paper’s data deceptive and uninterruptible and their conclusions are unsupported.

Guest Critic #2: F. Edward Yazbak, MD, FAAP

A Tale of Two Cities: Flawed Epidemiology

By F. Edward Yazbak, MD, FAAP

In July 2006, Fombonne et al published a report in PEDIATRICS about pervasive developmental disorders, MMR vaccination and Thimerosal. In a letter to the editor of the journal, I reported legitimate concerns about the MMR research and its conclusions. Both Dr. Fombonne and the editor chose to ignore them.


On February 2, 2007, I re-submitted a letter to the editor of PEDIATRICS about a study that had been published on July 6, 2006. PEDIATRICS is the journal of the American Academy of Pediatrics (AAP).

I have been a Fellow of the Academy since 1963. This was the first letter to the editor of the journal that I had ever written.

Following is the exact text of my letter:


In "Pervasive developmental disorders in Montreal, Quebec, Canada: prevalence and links with immunizations" (1) Fombonne et al reported that in a group of English-speaking Montreal children born from 1987 to 1998, the prevalence of pervasive developmental disorders (PDD) was high and increasing. They also claimed that during the same period, Measles-mumps-rubella (MMR) vaccination coverage had decreased and concluded "Thus, pervasive developmental disorder rates significantly increased when measles-mumps-rubella vaccination uptake rates significantly decreased."

The MMR uptake data used "were available through N. Bouliane, BN, MSc of the Direction de Santé Publique de la Capitale Nationale" and were "routinely collected in the region of Québec among 5-year-old children attending kindergarten during 1993-2004."

La Capitale Nationale refers to Quebec City, located 265 kilometers from Montreal. Ms. Bouliane confirmed that the MMR vaccination rates were indeed from the Quebec City area but refused to release them to me because they were administrative internal information only intended for research.

There are several published vaccine uptake surveys of Montreal. MMR vaccination rates of children 24 to 30 month-old in the Montreal area increased from 85.1% in 1983 (Baumgarten) (2) to 88.8% in 1996-97 (Valiquette) (3) to 96% in 2003-04 (Health Department Survey) (4)

The above suggests that in Montreal PDD prevalence and MMR vaccination rates were in fact increasing in tandem during the study period.

The readers deserve to know why the authors compared developmental data from a specific group of children in Montreal with MMR vaccination data from the city of Quebec, some distance away.


  • Fombonne E, Zakarian R, Bennett A, Meng L, McLean-Heywood D. Pervasive developmental disorders in Montreal, Quebec, Canada: prevalence and links with immunizations. Pediatrics. 2006 Jul;118(1):e139-50.
  • Annexe 1 of "Enquête sur la couverture vaccinale des enfants de 24 à 30 mois de Montréal-Centre" by Valiquette (1998).
  • Table 3 (page 20) of "Enquête sur la couverture vaccinale des enfants de 24 à 30 mois de Montréal-Centre" by Valiquette (1998)
  • Hudson Patricia et al, Are Montreal Children adequately vaccinated? Prevention en pratique médicale. Available on page 5 of

Conflict of Interest

The author is the grandfather of a child with autistic enterocolitis who has evidence of measles virus genomic RNA in the gut.


I received the following response:


Title: Far-Fetched
Manuscript number: 2007-0326

Dear Dr. F. Yazbak:

What follows is a copy of Dr. Fombonne's e-mail in response to your Letter-to-the-Editor.

"This person is known to pursue the MMR-autism agenda at all costs in order to 'demonstrate' a link he strongly believes in. The only way ahead is to encourage him to do independent research. All controlled epidemiological research thus far has concluded to the absence of such a link."

As a note, I believe the evidence of no link between MMR and Autism is sufficient. It's not worth publishing more on this subject. We will not be publishing this exchange of correspondence.

Thank you for thinking of Pediatrics.


Jerold F. Lucey, MD
Pediatrics Editorial Office


The first sentence in Dr. Fombonne's note is correct. I do believe that a link does exist between MMR vaccination and autism in certain genetically -predisposed children.

The rest of the message is inappropriate both in tone and content and Dr. Fombonne's statement that "all controlled epidemiological research thus far has concluded to the absence of such a link" is irrelevant and unrelated to my letter.

So is the editor's personal belief about the "link between MMR and Autism”.

I found and reported a glaring error in the paper. The rates of autism in Montreal have as much to do with MMR vaccination rates in Quebec City as pollution in Los Angeles with Diesel buses in Chicago.

The lead author refused to respond to my criticism concerning that simple geographic fact and the editor was unable to force him to do so.

It is as simple as that.

Furthermore, in order to "estimate the pervasive developmental disorder prevalence in Montreal", Dr. Fombonne only surveyed children enrolled in one of Montreal 's five school boards.

In 2003-2004, that particular English school board only had 14% of all total school boards enrollments in Montreal. In addition, this board was never representative of the true student demographic profile of the city, whose mother tongue is mostly French (43%), followed by various non-English languages (37%) and then English (22%). French and immigrant children who constitute the majority of the school population cannot attend English schools.

My submission to the electronic peer to peer review of PEDIATRICS, also a first, was not published as well.


In 2001, Dr. Fombonne reported in PEDIATRICS the results of another study that he had conducted in the United Kingdom. That publication titled "No evidence for a new variant of measles-mumps-rubella-induced autism" (1) was intended to rebuke Andrew Wakefield's theory. It received little or no attention.

It is not known how many relevant letters to the editor were rejected at the time.

Discussing the 2001 study in their comprehensive Cochrane MMR Review, Demichelli, Jefferson et al reported that "The numbers and possible impact of biases in this study is so high that interpretation of the results is impossible." (2)


When he was in France, Dr. Fombonne was a well known psychiatrist who published articles on psychiatric topics.

He was still a psychiatrist when he moved to England...until Andrew Wakefield suggested that the link between MMR vaccination and autism should be further investigated and suddenly...Dr. Fombonne became a "psychiatrist/epidemiologist" and a consultant to the UK medical authorities on MMR vaccination and autism. He published several articles on the subject including "No evidence for a new variant of measles-mumps-rubella-induced autism" in PEDIATRICS in 2001 (above) but avoided dealing with the Thimerosal issue.

Since his arrival to Montreal, Dr. Fombonne is Chair, Department of Psychiatry and Head of the Division of Child Psychiatry at McGill University. He is also the Director of the Department of Psychiatry at the Montreal Children's Hospital, yet the lay press often refers to him as an "Epidemiologist".

Dr. Fombonne was also recognized as an "Epidemiologist" in a Thimerosal-related case in a U.S. Court.

A footnote in the July 2006 publication "Pervasive developmental disorders in Montreal, Quebec, Canada: prevalence and links with immunizations" reads: "In the United Kingdom, Dr Fombonne has provided advice on the epidemiology and clinical aspects of autism to scientists advising parents, to vaccine manufacturers, and to several government committees between 1998 and 2001. Since June 2004, Dr. Fombonne has been an expert witness for vaccine manufacturers in US thimerosal litigation. None of his research has ever been funded by the industry."

It is obviously customary to disclose sources of funding, Disclosing sources of "Non-Funding" on the other hand is unusual. In any case, it is nice to know that Dr. Fombonne's research was never funded by the "Industry".

The statement proves what I mentioned earlier: That Dr. Fombonne only became interested in MMR vaccination in the UK after Andrew Wakefield published his original research on the subject in 1998. It also raises an important question: How did Dr. Fombonne become an "expert witness for vaccine manufacturers" in 2004 when his very first research on Thimerosal was just published in PEDIATRICS on July 6, 2006?

No wonder "Pervasive developmental disorders in Montreal, Quebec, Canada: prevalence and links with immunizations" was so important to "protect" and it is no surprise that Dr. Fombonne chose not to respond to my letter. Besides, what could he have said and how could he have justified the strange fact that he compared developmental information about a specific group of children in Montreal with unrelated MMR vaccination data from Quebec City, a good distance away?


Footnote: I am not anti-vaccine nor have I ever been.


1. Fombonne E, Chakrabarti S. No evidence for a new variant of measles-mumps- rubella-induced autism. Pediatrics. 2001 Oct;108(4):E58.
1. Demicheli V, Jefferson T, Rivetti A, Price D. Vaccines for measles, mumps and rubella in children. Cochrane Database Syst Rev. 2005 Oct 19;(4):CD004407. Review

F. Edward Yazbak, MD, FAAP

TL Autism Research
Falmouth, Massachusetts
March 7, 2007