WE read your
report, Mercury linked to autism (June 19), with some
dismay that yet again a single unpublished study that
has not been subjected to critical scientific scrutiny
has gener-ated such an alarmist headline. Such articles,
adorned with quotes from the usual band of crusading
commentators who use any study, however flawed, to
justify their beliefs, are misleading and irresponsible.
Many suppositions are made in your report that fly in
the face of common sense, logic, established facts, and
other scientific evidence.
Much publicity has been given to those who advocate
that the MMR vaccine is the cause of the rising numbers
of children being diagnosed as having an autistic
spectrum disorder. This MMR scare began in 1998 with a
study by Dr Wakefield et al published in the Lancet. The
study has since been widely discred-ited and no valid
scientific evidence has ever been produced to support
such a hypothesis. On the contrary, a large number of
rigorous scientific studies have testified to the
vaccine's safety and absence of linkage with autism. The
MMR vaccine does not contain thiomersal.
Having failed to demonstrate the culpability of the
MMR vaccine, we are now being told that it is
thiomersal, a preservative present in a certain brand of
the Diphtheria/Pertussis/ Tetanus vaccine (DTP), that is
the cause of the perceived rise in autism in recent
years. Better diagnosis and changes in diagnostic
classification are often ignored as at least part of the
explanation for the rise. This assertion is strange in
the context that DTP vaccine has been in use for over 60
years and yet this claimed "epidemic of autism" is a
relatively new phenomenon. In addition it is also the
case that the amounts of thiomersal received by children
from the infant immunisation programme in the UK have
decreased in recent times. These facts clearly
contradict a causal relationship between thiomersal and
recent rises in autism.
Almost all previous studies on the toxicological
effects of heavy metals such as mercury and lead have
substantiated a positive correlation between very high
levels of these substances found in hair and an
increasing adverse effect on neuro-logical development.
Whereas in this quoted study the amount of mercury found
in the hair of autistic children is less than in the
non-autistic children. Yet somehow it is hypothesised,
without any evidence, that mercury build- up somewhere
else in the body is responsible for their autistic
symptoms.
Finally, it is the view of this department that such
unsubstantiated and ill-founded claims are detrimental
to public confidence in the childhood vaccination
programme. This programme has been an outstanding
success in eradicating serious and life- threatening
infections in recent times. Irresponsible scaremongering
could eventually result in death and serious disability
in many children if these diseases are allowed to return
due to low vaccine- uptake.
It is also a cruel blow to all those parents of
autistic children who are now being erroneously informed
that they have permanently damaged their own children
because of their responsible actions in attempting to
protect their loved ones against the consequences of
contracting such diseases.
Vincent McKeown, public health nurse; Dr Syed Ahmed,
immunisation co-ordinator, Public Health, Greater
Glasgow NHS Board, 350 St Vincent Street, Glasgow.
