New NIH funded study on thimerosal

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http://ehp.niehs.nih.gov/members/2005/7712/7712.pdf

 

THE BIG PICTURE...................

 

" The large difference in the blood Hg half-life compared to the

brain half-life

for

 

the thimerosal-exposed infants (6.9 days vs 24 days) indicates that

blood Hg may

not be a

 

good indicator of risk of adverse effects on the brain, particularly

under

conditions of

 

rapidly changing blood levels such as those observed following

vaccinations. The

blood

 

concentrations of the thimerosal-exposed infants in the current

study are within

the range

 

of those reported for human infants following vaccination (Stajich

et al 2000).

Data from

 

the current study predicts that while little accumulation of Hg in

the blood

occurs over

 

time with repeated vaccinations, accumulation of Hg in the brain of

infants will

occur.

 

Thus, conclusion regarding the safety of thimerosl drawn from blood

Hg clearance

data

 

in human infants receiving vaccines may not be valid, given the

significantly

slower halflife

 

of Hg in the brain as observed in the infant macaques.

 

There was a much higher proportion of inorganic Hg in the brain of

thimerosal

 

infants than MeHg infants (up to 71% vs. 10%). Absolute inorganic Hg

concentrations in

 

the brains of the thimerosal-exposed infants were approximately

twice that of

the MeHg

 

infants. Interestingly, the inorganic fraction in the kidneys of the

same cohort

of infants

 

was also significantly higher following i.m. thimerosal than oral

MeHg exposure

 

(0.71±0.04 vs. 0.40±0.03). This suggest that the dealkylation of

ethylmercury is

much

 

more extensive than that of MeHg. "

 

 

Donna