What Is Thimerosal?
Thimerosal, also known as sodium thimerosalate, is a mercury-containing organic compound that has long been widely used as a preservative in biological products and pharmaceutical preparations including many vaccines to prevent potential hazards caused by harmful microbial contamination. In the history of biological products, the application of preservatives such as thimerosal has been over 60 years.
Thimerosal
- Thimerosal, also known as sodium thimerosalate, is a mercury-containing
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- C9H9O2HgNaS
- It is a milky white to slightly yellow crystalline powder; it is slightly special smelly and slightly hygroscopic. Deterioration in case of light. 1% aqueous solution pH 6-8. Easily soluble in water and ethanol, insoluble
- For disinfecting preservatives and in
- 0.1% anhydride for skin disinfection before surgery; 0.1% solution for disinfection of planed surfaces; 0.01% 0.02% solution for eye, nose and urethral irrigation; 0.1% cream for treating fungal skin infections; 0.02% is used in biological products as bacteriostatic agent, 1% thimerosal solution vaccine preservative.
- Not compatible with acids, iodine, aluminum and other heavy metal salts or alkaloids.
- Thimersal Thimersalati: 1g per 10,000ml of thimerosal,
- Protect from light and airtight.
- Can cause contact dermatitis, allergic conjunctivitis, ototoxicity.
- Its toxic effect is currently under debate, see the following two paragraphs for details.
- In 1999, the United States raised concerns about exposure to mercury after immunization. This is based on the recognition that according to infant immunization protocols, accumulated mercury levels may exceed the allowable value of methylmercury recommended and regulated by the US government. However, thimerosal, as a preservative for some vaccines, is not methylmercury but ethylmercury. The Global Vaccine Safety Advisory Committee assessed this issue for the first time at a special meeting in August 2000,
- The conclusion is that there is currently no evidence that thiomersal (containing ethyl mercury) in the vaccine is toxic to infants, children, or adults to whom it is exposed. The Committee has continued its deliberations since then.
- Since August 2000, the WHO Global Advisory Committee on Vaccine Safety has regularly reviewed information on the available pharmacokinetics of thimerosal in humans, including low birth weight infants and monkeys, and has evaluated studies on thimerosal and human neurodevelopmental disorders (Such as autism) correctness of animal models of correlation.
- Expert consultations and data provided to the Global Advisory Committee on Vaccine Safety show that the pharmacokinetic characteristics of ethylmercury differ substantially from methylmercury. In particular, the half-life of ethylmercury is short compared to the half-life of methylmercury from 40 to 50 days (6 days, 95% CI: 3-10 days), which makes the exposure time of ethylmercury in the blood relatively Short, and at the same time, at least four weeks apart will prevent accumulation. In addition, ethylmercury is actively eliminated through the intestine and does not accumulate in the body like methylmercury. All studies reviewed, even those of low birth weight infants, confirmed rapid removal of ethylmercury.
- Four independent epidemiological studies were conducted in the UK and Denmark to investigate the link between the frequency of neurodevelopmental disorders and immunization with thimerosal-containing vaccines. These studies did not challenge the safety of infants with existing thimerosal-containing vaccines.
- The Global Vaccine Safety Advisory Committee also reviewed a series of studies carried out by Gail and Gail, which claimed that neurodevelopmental disorders have decreased in the United States as the national immunization program stopped using vaccines containing thimerosal. The Commission identified a number of methodological limitations, as a result of which the published results regarding neurodevelopmental disorders and heart disease following the injection of thimerosal-containing vaccine failed to meet scientific standards for demonstrating causality. The Committee therefore considers that the authors' conclusions are neither persuasive nor factual.
- Based on this, the Global Advisory Committee on Vaccine Safety believes that the pharmacokinetic and developmental studies carried out cannot support concerns about the safety of thimerosal in vaccines.
- The Commission also concluded that there were no safety reasons to change the current immunization practice with thimerosal vaccines, and the so-called risks have not been proven.
- The use of thimerosal in childhood vaccines is now banned in Iowa, California, the United Kingdom, and other European countries.
- safety
- The mercury contained in the vaccine is actually thimerosal, which is a local bactericide and contains approximately 50% mercury organic matter. Since 1930, it has been widely used in drugs (such as eye drops, ear drops, immunoglobulins, cosmetics, etc.) and vaccines. Its main function is to act as a "preservative" to prevent the preparation from being contaminated by bacteria or microorganisms, and thus to prevent serious sequelae caused by being put into the human body.
- Especially for large-dose vaccines, thiomersal is necessary because of the need for multiple people to give the same dose of bottle, which is likely to cause infection due to repeated suction. Generally speaking, the mercury content in the vaccine is about 0.003% to 0.01%. At such low concentrations, mercury can effectively inhibit the growth of bacteria or molds. Therefore, the mercury in the vaccine is mainly to make the vaccine safer. .
- In addition, the vaccine also contains saline, formaldehyde and aluminum salts, each of which plays an important role to maintain the safety and stability of the vaccine. In addition, the ingredients in the vaccine have been tested and verified to be harmless to the human body before being added.
- Like thimerosal, before the market launch in 1930, it has been confirmed by many research reports that low doses have not significantly harmed human and animal experiments. However, in 1950, chlor-alkali factories in Japan discharged mercury-containing wastewater into the sea, causing marine organisms to absorb it and accumulate in the body, and then caused collective mercury poisoning after being consumed by humans. In 1970, Iraq also suffered from mercury-containing insecticides. Thousands of people were killed by pesticide contamination of rice, and then everyone began to pay attention to the problem of mercury toxicity. [1]