A
new study, which had been designed to detect a link between
the rise in autism and the mercury in vaccines, found
no such danger to children born in the 1990s when the
greatest number of mercury-containing vaccinations was
administered. The feel-good results, from the U.S. Centers
for Disease Control and Prevention (CDC), were immediately
challenged by an advocacy organization armed with documents
obtained through the Freedom of Information Act.
Thimerosal
is a mercury-based preservative added to vaccines in order
to prevent bacterial contamination. Even at low levels,
mercury has long been known to be a potent toxin with
adverse effects on the brains and nervous systems of fetuses
and young children.
Thimerosal
has been in vaccines since the 1930s, but the amount in
each vaccine is so minute that safety was never an issue
until the standard vaccination regimen expanded and tripled
the dose of mercury administered to infants in the first
months of life. A baby born in the 1990s received as many
as 17 vaccinations for up to ten different diseases in
the first 18 months of life. The regimen typically began
within hours of birth and continued every two months thereafter.
(A baby born in the 1940s would have received one
vaccination around age five.)
The
cumulative effect of a known toxin in the small body of
an infant or toddler led the Food and Drug Administration
(FDA), in 1999, to ask manufacturers to voluntarily remove
thimerosal from the vaccines routinely administered to
children. The FDA action was based on the belated realization
among public health officials that the mercury exposure
from vaccines had become higher than the safe threshold
set by the federal guidelines for food sources of mercury
(e.g., large fish).
As
things stand now, the schedule of vaccines administered
to babies under 18 months has expanded to include the
pneumonia and flu vaccines, but thimerosal has been removed
from most of the products*. Mercury-related concerns center
upon the children born in the era when the mercury burden
was highest. There is a growing suspicion that mercury
is implicated in the dramatic increase in the number of
children diagnosed with a neurological disorder called
autism. This possibility got a boost from a 2001 Institute
of Medicine report that concluded, it was “biologically
plausible,” though not proven, that thimerosal could be
related to neurodevelopmental delays in some children.
The
prevalence of autism is estimated by the CDC to be ten
times higher today than it was in the studies conducted
in the U.S. during the 1980s and early 1990s. The rate
now is approximately one in 300. The incidence of autism
is four times more common in boys. The potential for lawsuits
is extremely high should the link between autism and thimerosal
ever be confirmed.
The
Centers for Disease Control (CDC) may not be the most
objective group to settle the question of thimerosal safety,
as it is the federal agency that mandates the number and
type of childhood vaccinations. The new study was led
by the CDC's Thomas Verstraeten, MD, and published in
the November issue of Pediatrics, the journal of the American
Academy of Pediatrics. Dr. Verstraeten now works for GlaxoSmithKline,
one of the world's largest vaccine manufacturers.
The
new CDC study looked at more than 140,000 infants who
were born in the 1990s and were in the care of three large
HMOs. An increase in tics and language delay was found
to be associated with cumulative exposure to mercury in
the first 3-7 months of life. “No consistent significant
associations were found between thimerosal-containing
vaccines and neurodevelopmental outcomes,” concluded the
CDC study.
But
Dr. Verstraeten and colleagues did initially find a statistically
significant link between thimerosal and autism. This is
evident from documents obtained through the Freedom of
Information Act by Safe Minds, an organization funded
primarily by parents of autistic children. Included in
these documents are the original study and the changes
made thereafter. The most interesting document contains
“highlights” of the discussions from a closed meeting
in 2000 when CDC and other officials gathered to decide
what to do next—after the first phase of the study indicated
an increase in autism among children subjected to the
highest level of mercury exposure.
In
the transcript of the meeting, the physicians, scientists
and vaccine company executives come across less as truth
seekers than as people exploring ways to change the methodology
for the next phase of the study in order to come up with
a more favorable conclusion. Several spoke as if they
wished the study had never have been initiated in the
first place. One physician at the meeting said that he
did not want his newborn grandson to get a thimerosal-containing
vaccine “until we know better what is going on.” Two weeks
later, the same physician, who is a member of the CDC's
Advisory Committee on Immunization Practices, voted against
a policy of telling parents to request thimerosal-free
vaccines for their babies, according to Safe Minds.
The
documents show that the CDC study went through major changes
on the way to publication. According to an analysis of
these documents conducted by Safe Minds, the HMO databases
used for the subsequent phase of the study appear to have
been selected to “skew the results” and find “inconsistencies”
in the data.
According
to the Safe Minds spokesperson Sallie Bernard, Dr. Verstraeten,
who is the lead author of the study, should not have been
listed as a CDC employee when the study was published
in November 2003. “Dr. Verstraeten left the CDC in 2001
to work for GlaxoSmithKline,” she said in a telephone
interview. “The study went through many major changes
since then, and as the lead author, Dr. Verstraeten was
responsible for overseeing these alterations, which were
done while he was an employee of the vaccine company.”
For
More Information:
The
documents retrieved from the CDC through the Freedom of
Information Act are available at www.safeminds.org.
Safe Minds describes itself as an organization that encourages
research efforts to understand scientifically how mercury
may be causing health problems and to identify effective
treatments. The organization is working to have mercury
removed from all medical products. It provides lists of
currently used thimerosal-containing medical products
(by brand) for children and adults, as well as information
about environmental and food sources of mercury.
*There
are a few exceptions, such as some of brands of the flu
vaccine currently advised for babies over age six months.
Maryann
Napoli, January 2004
