Nowadays most vaccines don't contain thiomersal anymore, nor is it still believed that occasional ingestion of tiny amounts of thiomersal is harmful:
Thiomersal is an
organomercury compound used as a preservative in vaccines since the 1930s to prevent
bacterial and
fungal contamination.[SUP]
[5][/SUP] Following a mandated review of mercury-containing food and drugs, the
Centers for Disease Control and Prevention (CDC) and the
American Academy of Pediatrics (AAP) asked vaccine makers to remove thiomersal from vaccines as quickly as possible as a purely precautionary measure, and it was rapidly phased out of most U.S. and European vaccines.[SUP]
[6][/SUP][SUP]
[7][/SUP] In the context of perceived increased autism rates and increased number of vaccines in the childhood vaccination schedule, some parents believed the action to remove thiomersal was an indication that the preservative caused autism.[SUP]
[6][/SUP]
The potential impact of thiomersal on autism has been investigated extensively. Multiple lines of scientific evidence have shown that thiomersal does not cause autism. For example, the clinical symptoms of
mercury poisoning differ significantly from those of autism.[SUP]
[8][/SUP] In addition, multiple population studies have found no association between thiomersal and autism, and rates of autism have continued to increase despite removal of thiomersal from vaccines.[SUP]
[3][/SUP] Thus, major scientific and medical bodies such as the
Institute of Medicine[SUP]
[2][/SUP] and
World Health Organization[SUP]
[9][/SUP] (WHO) as well as governmental agencies such as the
Food and Drug Administration[SUP]
[5][/SUP] (FDA) and the CDC[SUP]
[10][/SUP] reject any role for thiomersal in autism or other neurodevelopmental disorders. In spite of the consensus of the scientific community, some parents and advocacy groups continue to contend that thiomersal is linked to autism.[SUP]
[11][/SUP]
Thiomersal controversy - Wikipedia, the free encyclopedia
Or as RationalWiki put it:
Thiomersal (also commonly known by its U.S. marketing name "Thimerosal") is a
mercury-containing compound used as a preservative in many vaccines. The fact that some mercury compounds are
toxic has led many to conclude that vaccines containing this compound are dangerous. Many mercury compounds, particularly those with mercury-
carbon bonds,
are neurotoxins, such as dimethylmercury.[SUP]
[10][/SUP] While in large doses thiomersal can be toxic, a 2002 study indicated that the mercury levels in infants receiving a vaccine preserved by an appropriate amount of thiomersal were low; some were so low that they could
not be measured. The toxicity of mercury compounds found in fish oil pills is likely to exceed that of thiomersal. By definition, this means the blood concentrations of mercury were below the
EPA guidelines. (The amount of mercury in stool samples was higher than normal, although this is an indicator that the body was eliminating the thiomersal, rather than accumulating it.[SUP]
[11][/SUP][SUP]
[12][/SUP]) Most of the concern about thiomersal derives from analogy with methylmercury, a well characterized mercury compound, but it is unclear whether the actual pharmacology is similar to thiomersal — after all,
ethanol and methanol are
extremely similar molecules but have quite different effects on the body.[SUP]
[13][/SUP] Initial studies on the pharmacokinetics indicate several differences between methylmercury and thiomersal.[SUP]
[14][/SUP] The amount of thimerosal actually present in vaccines is quite low and, most importantly, there are large studies available that have shown no evidence of harm.[SUP]
[15][/SUP]
Anti-vaccination movement - RationalWiki
