So what else happened in Denmark? 1 October 2004
F. Edward Yazbak,
Pediatrician, Director
TL Autism Research, Falmouth, Massachusetts 02540, USA
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Re: So what else happened in Denmark?

 Autism has increased in Denmark (1, 2) since the introduction of the MMR
vaccine in 1987.

So what else happened in Denmark?

. Among 2520 randomly selected children in Denmark, nearly all (98%) nine
year-old children had IgG antibodies to measles virus BEFORE the MMR
campaign started (3)

. In response to a 1991 questionnaire, 29% of the general practitioners in
Denmark were less positive about vaccination for measles, mumps and rubella
(MMR) than about the remainder of the recommended childhood vaccinations (4)

. Also in 1991, only 56% of 171 practitioners interviewed expressed a
whole-hearted positive attitude towards MMR Vaccination. The average
vaccination rate in practices with unreservedly positive attitudes was 85%,
compared with 69% in practices with more guarded attitudes (5)

. In 1992, a predictive study extending to 2002 revealed that compliance
with vaccination among 12-year-olds had to quickly improve in order to
maintain the level of immunity that was present prior to institution of the
MMR vaccination program (6)

It is clear from the above, that the MMR vaccination rates in Denmark in
the early nineties were not very high. As shown by Goldman (1), when the
majority of children in Denmark had received the MMR vaccine and when those
children were old enough to be diagnosed with autism (around age 5), the
increase in the prevalence of autism was evident.

Children included in the Madsen (7) MMR study were born between January 1,
1991 and December 31, 1998. Many of those born in the first four years had
not received the MMR vaccine and many of the affected children born in the
last four years were too young to have been diagnosed. By studying the
period between 1980 and 2002, Goldman was able to report more accurate

Noteworthy is the fact that Madsen himself published another study (8)
about autism in Denmark, just ten months after his NEJM report, in which he
stated: "From 1991 until 2000, the incidence increased and continued to
rise after the removal of thimerosal from vaccines, including increases
among children born after discontinuation of thimerosal."

Those same figures should have been available to Madsen in 2002 when he
published his research, that was co-sponsored by the CDC, in the New
England Journal of Medicine.

Dr. Madsen seems confident that the increase in autism in Denmark after the
removal of Thimerosal from pediatric vaccines is real.


1. Goldman GS, Yazbak FE: An Investigation of the Association between MMR
Vaccination and Autism in Denmark. JAmPhysSurg 2004; 9(3):70-75

2. Stott C, Blaxill M, Wakefield AJ: MMR and Autism in Perspective: The
Denmark Story. JAmPhysSurg 2004; 9(3):89-91

3. Glikmann G, Petersen I, Mordhorst CH. Prevalence of IgG-antibodies to
mumps and measles virus in non-vaccinated children: Dan Med Bull 1988
Apr;35(2):185-7 [PMID: 3359817]

4. Johansen M, Haurum J. Attitudes to and knowledge of contraindications
against measles, mumps and rubella vaccination (MFR- vaccination) among
general practitioners [Danish] Ugeskr Laeger 1991 Mar 4;153(10):709-12
[PMID: 2008714]

5. Trier H. Doctors' attitudes and MMR-vaccination. Scand J Prim Health
Care 1991 Mar;9(1):29-33 [PMID: 2041925]

6. Ronne T, Trier H. Changes in measles, mumps and rubella (MMR) immunity
until the year of 2002 after the introduction of MMR vaccination [Danish]
Ugeskr Laeger 1992 Jul 13;154(29):2014-8 [PMID: 1509567]

7. Madsen KM, Hviid A, Vestergaard M, Schendel D, Wohlfahrt J, Thorsen P,
Olsen J, Melbye M. A population-based study of measles, mumps, and rubella
vaccination and autism. N Engl J Med. 2002 Nov 7;347(19):1477- 82.

8. Madsen KM, Lauritsen MB, Pedersen CB, Thorsen P, Plesner AM, Andersen
PH, Mortensen PB. Thimerosal and the occurrence of autism: negative
ecological evidence from Danish population-based data. Pediatrics. 2003
Sep;112(3 Pt 1):604-6.

Competing interests: Grandfather of a boy with autism who has evidence of
measles virus genomic RNA in the intestinal wall