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Analysis And Comment Public health

Influenza vaccination: policy versus evidence

BMJ 2006; 333 doi: (Published 26 October 2006) Cite this as: BMJ 2006;333:912

Rapid Response:

Side effects of mercury containing vaccines like influenza

Sir: Tom Jefferson notes that there are no sound studies regarding
the safety of vaccines [1]. This is especially true for thimerosal in
vaccines, an organic mercury compound.

Most vaccines, especially for developing countries, contain
thimerosal, an organic mercury compound.

It has been shown recently that this additional mercury body burden
may be a factor for the development of autism [2].

In the U.S. there are actually 1.5 Million children diagnosed with
austism spectrum disorders (ASD) and additional thimerosal containing
vaccines may have caused this epidemic 16 years ago [3].

Many reviews regarding this topic state that the increase in the
incidence of autism occured mostly after cessation of thimerosal-containing vaccine use, which is an argument against this hypothesis [4].
But these studies have many methodological flaws. For example one study,
which was done in Denmark, found that autism cases rose after cessation
of thimerosal-containing vaccines [5].

Two important methodical flaws must be noted:

(i) Autism counts were based on inpatient records in the first cohort and
then changed in the middle of the study period (1995) to include
outpatient records. Outpatients exceeded the inpatients by a ratio of 13.5.

(ii) After 1992, the registry added inpatients, , from a Copenhagen clinic
who had been excluded prior to 1992; this accounted for 20% of the
caseload in Denmark.
Therefore the increase of autism may be caused solely by a tremendous
increase in the study population.

Interestingly, thimerosal was introduced in 1931 in vaccinations and
regressive autism was first described in 1943 in children born in the
1930s by Dr. Kanner.

It should be noted that after removing thimerosal from most vaccines
(exept influenza) in the U.S., the prevalence of autism is for the first time in the
medical history decreasing [6].

1. Jefferson T. Influenza vaccination: policy versus evidence. BMJ
2006; 333: 28 October

2. Mutter J, Naumann J, Schneider R, Walach H, Haley B. Mercury and
autism: Accelerating Evidence? Neuro Endocrinol Lett 2005; 26: 431-7.

3. Bernard S, Enayati A, Roger H, Binstock T, Redwood L. The role of
mercury in the pathogenesis of autism. Mol. Psychiatry 2002; 7: S42-3.

4. Kurita H. Disorders of the autism spectrum. Lancet 2006; 368:179-

5. Madsen KM, Lauritsen MB, Pedersen CB, Thorsten P, Plesner AM et
al. Thimerosal and the Occurrence of Autism: Negative Ecological Evidence
From Danish Population-Based Data. Pediatrics 2003; 112: 604-6.

6. Geier DA, Geier MR. An assessment of downward trends in
neurodevelopmental disorders in the United States following removal of
Thimerosal from childhood vaccines. Med Sci Monit 2006; 12:CR231-9.

Competing interests:
None declared

Competing interests: No competing interests

22 November 2006
Joachim Mutter
Medical Doctor
Hospital Epidemiology, University Medical Center, Breisacherstr. 115 B, 79106 Freiburg