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Medical Forum / General / Alternative / May 2005Thimerosal Studies
http://www.niaid.nih.gov/factsheets/thimerosalqa.htm NIAID-Supported Studies on Mercury, Thimerosal, and Vaccine Safety Overview Thimerosal is a preservative that has been added to some vaccines and other products because it is effective in killing bacteria and in preventing bacterial contamination. When thimerosal is degraded or metabolized, one product is ethyl mercury. In July 1999, U.S. Department of Health and Human Service (DHHS) agencies, including the National Institute of Allergy and Infectious Diseases (NIAID); The American Academy of Pediatrics; and vaccine manufacturers agreed that thimerosal should be reduced or eliminated in vaccines as a precautionary measure and to reduce exposure to mercury from all sources. This decision was based on the various Federal guidelines for methyl mercury exposure and the assumption that the health risks from methyl and ethyl mercury were the same. More research is needed to determine if the guidelines for methyl mercury are also appropriate guidelines for thimerosal. NIAID thimerosal research focuses on better understanding what happens to thimerosal once it is introduced in the body and how this compares to current knowledge of methyl mercury pathways. How does methyl mercury exposure differ from thimerosal exposure? There are important differences between methyl mercury exposure and thimerosal exposure. a.. Thimerosal contains ethyl mercury, which is structurally different from methyl mercury. b.. The timing and route of exposure are different for these two chemicals. People mainly become exposed to methyl mercury through eating fish. Some of this methyl mercury may be passed from the mother to the fetus before birth and to infants through breast milk. Prior to the removal of thimerosal from childhood recommended vaccines, infants were exposed to thimerosal by intramuscular injection during vaccination, not by ingestion. Furthermore, infants received thimerosal from vaccines that were administered days or months apart. In contrast, methyl mercury exposure, primarily from foods, tends to occur over a longer, sustained period of time. What is known about prenatal exposures to ethyl mercury? There is minimal modern research to address whether or not ethyl mercury may be passed from the mother to the fetus before birth. As a precaution, DHHS and product manufacturers are working to reduce or eliminate thimerosal from products that may be given to pregnant women, such as Rho (D) Immune Globulin. Also, thimerosal-free versions of several adult vaccines are available for use. Are the current mercury guidelines appropriate for assessing thimerosal exposure? Methyl mercury guidelines assess a child's risk based on a continuing daily mercury exposure. As mentioned above, there are several important differences between methyl mercury exposure and thimerosal exposure. More research is needed to determine if the guidelines for methyl mercury exposure are also appropriate guidelines for thimerosal. What research is NIAID funding to find out more about the effects of thimerosal exposure and how it compares with methyl mercury exposure? NIAID has supported several studies to address these questions, including a.. One completed study of mercury levels in infants who received vaccines containing thimerosal b.. Two follow-up studies of mercury levels in infants who receive vaccines containing thimerosal c.. One ongoing study of thimerosal and methyl mercury exposure in infant monkeys What was the purpose of the published study about thimerosal and vaccinations? NIAID-supported studies at the University of Rochester and National Naval Medical Center in Bethesda, MD, looked at levels of mercury in blood and other samples from 61 infants who had received routine immunizations with thimerosal-containing vaccines. What types of samples were assessed? Mercury levels were measured in blood, urine, and stool samples from infants at different times up to 28 days after vaccination. Researchers also looked at levels of mercury in samples of breast milk, mother's hair, and infant formula. What were the primary results obtained from assessment of these samples? a.. Blood levels of mercury were uniformly below safety guidelines for methyl mercury for all infants in this study. b.. Mercury was cleared from the blood in infants exposed to thimerosal faster than would be predicted for methyl mercury. c.. Infants excreted significant amounts of mercury in stool after thimerosal exposure, thus removing mercury from their bodies What can be concluded from the results of the Rochester study? These results suggest that there are differences in the way that thimerosal and methyl mercury are distributed, metabolized, and excreted. Thimerosal appears to be removed from the blood and body more rapidly than methyl mercury. Where can I find more information on the Rochester study? The results have been published in the November 30, 2002, issue of the scientific journal, The Lancet. Reference: Pichichero ME, Cernichiari E, Lopreiato J, and Treanor J. Mercury concentrations and metabolism in infants receiving vaccines containing thimerosal: a descriptive study. Lancet 360:1737-1741 (2002). The Lancet online: http://www.thelancet.com Does NIAID plan to support any further research to assess mercury levels in infants who received vaccines containing thimerosal? Yes. NIAID is supporting a follow-up study with a larger number of infants. The University of Rochester is collaborating with the Children's Hospital of Buenos Aires in Argentina to conduct this study. The Argentina clinicians are measuring mercury in blood and other samples from infants receiving routine vaccinations with thimerosal. NIAID also plans to conduct an additional study in Argentina that will focus on enrollment of premature (32 to 37 weeks gestational age) and low birth weight (2000 to <3000 grams) infants. Although some thimerosal-containing vaccines still are given to children in Argentina, most vaccines now given to children in the United States are either thimerosal-free or contain markedly reduced amounts of thimerosal. What does NIAID hope to learn from the follow-up studies of thimerosal and vaccines in infants? The goals of these studies are to assess the levels of mercury in the blood and other samples from infants receiving thimerosal-containing vaccines as part of their routine immunization schedule and to obtain more samples closer to the time of vaccination. What is the purpose of the ongoing studies of thimerosal and methyl mercury exposure in infant monkeys? NIAID is supporting studies in infant and adolescent monkeys to compare the distribution, metabolism, and clearance of mercury after exposure to thimerosal and methyl mercury. Infant monkeys were exposed to either thimerosal or methyl mercury on a weekly basis. Blood levels of mercury were determined for each animal after each exposure. The development and behavior of the monkeys has also been monitored. After the fourth dose, animal tissues were analyzed to determine levels of mercury in target tissues, such as brain and kidney. These studies will provide information to help determine whether or not the guidelines for methyl mercury are also appropriate for thimerosal. Are the results available for the ongoing studies of thimerosal and methyl mercury exposure in infant monkeys? Currently the investigators of this study are completing their analyses of the data obtained from this study. Preliminary results from these studies indicate a.. Mercury, in the form of methyl mercury (oral ingestion) and thimerosal (intramuscular injection with vaccines) were both readily absorbed and distributed into blood and brain. b.. Total (organic plus inorganic) mercury was cleared from both blood and brain faster after thimerosal exposure than after methyl mercury exposure. c.. Levels of total mercury measured in blood and in brain were lower after thimerosal exposure than after methyl mercury exposure. d.. The proportion of brain mercury that was inorganic was higher in animals exposed to thimerosal compared with methyl mercury. e.. The absolute amount of inorganic mercury was higher in thimerosal exposed animals compared with methyl mercury. f.. During weekly doses of methyl mercury, total mercury in blood continued to accumulate, while during weekly doses of thimerosal, there was little accumulation of total mercury in blood. This study indicates that methyl mercury is not a suitable reference for risk assessment from exposure to thimerosal. This study was not designed to measure any type of damage due to mercury exposure. The mechanisms by which organic mercury is converted to inorganic mercury in the brain are unknown. There is not a consensus as to whether inorganic mercury in brain causes damage or to what extent compared to organic mercury. These results were recently published in Environmental Health Perspectives. For more information, see http://ehp.niehs.nih.gov/docs/2005/7712/abstract.html. -------------------------------------------------------------------------------- NIAID is a component of the National Institutes of Health (NIH), which is an agency of the Department of Health and Human Services. NIAID supports basic and applied research to prevent, diagnose, and treat infectious and immune-mediated illnesses, including HIV/AIDS and other sexually transmitted diseases, illness from potential agents of bioterrorism, tuberculosis, malaria, autoimmune disorders, asthma and allergies. News releases, fact sheets and other NIAID-related materials are available on the NIAID Web site at http://www.niaid.nih.gov. Prepared by: Office of Communications and Public Liaison National Institute of Allergy and Infectious Diseases National Institutes of Health Bethesda, MD 20892 > http://www.niaid.nih.gov/factsheets/thimerosalqa.htm Excellent! Jan is now using something that is fact based. I will snip for focus, as this article addresses two claims her posts have made in recent days: 1. That thimerosal passes the blood-brain barrier. 2. That the mercury from thimerosal is stored in the brain. <snip> > What research is NIAID funding to find out more about the effects of > thimerosal exposure and how it compares with methyl mercury exposure? > [quoted text clipped - 26 lines] > a.. Blood levels of mercury were uniformly below safety guidelines for > methyl mercury for all infants in this study. One of the major claims by the anti-vac liars is that the effects are cumulative, since they always seem to add up the total exposure. This says that they were wrong/lieing. > b.. Mercury was cleared from the blood in infants exposed to thimerosal > faster than would be predicted for methyl mercury. Thus, do not feed infants fish. > c.. Infants excreted significant amounts of mercury in stool after > thimerosal exposure, thus removing mercury from their bodies. This is consistent with, and supports, the study that I posted showing that infants eliminate the mercury from thimerosal exposure rapidly. Logic dictates that if it is rapidly eliminated, it is not stored. > What can be concluded from the results of the Rochester study? > These results suggest that there are differences in the way that thimerosal > and methyl mercury are distributed, metabolized, and excreted. Thimerosal > appears to be removed from the blood and body more rapidly than methyl > mercury. Exactly! > Where can I find more information on the Rochester study? > [quoted text clipped - 5 lines] > thimerosal: a descriptive study. Lancet 360:1737-1741 (2002). The Lancet > online: http://www.thelancet.com That is the study that I posted. Does Jan see the error of her ways? > Does NIAID plan to support any further research to assess mercury levels in > infants who received vaccines containing thimerosal? [quoted text clipped - 43 lines] > (intramuscular injection with vaccines) were both readily absorbed and > distributed into blood and brain. Thus, there is evidence that ethyl mercury does pass the blood-brain barrier. > b.. Total (organic plus inorganic) mercury was cleared from both blood and > brain faster after thimerosal exposure than after methyl mercury exposure. > c.. Levels of total mercury measured in blood and in brain were lower > after thimerosal exposure than after methyl mercury exposure. Thus showing that Thimeorsal exposure cannot be equated with other mercury exposures. > d.. The proportion of brain mercury that was inorganic was higher in > animals exposed to thimerosal compared with methyl mercury. [quoted text clipped - 3 lines] > continued to accumulate, while during weekly doses of thimerosal, there was > little accumulation of total mercury in blood. Very interesting...seems that the rapid clearance prevents accumulation... > This study indicates that methyl mercury is not a suitable reference for > risk assessment from exposure to thimerosal. This study was not designed to [quoted text clipped - 6 lines] > For more information, see > http://ehp.niehs.nih.gov/docs/2005/7712/abstract.html. >> http://www.niaid.nih.gov/factsheets/thimerosalqa.htm > [quoted text clipped - 4 lines] > 1. That thimerosal passes the blood-brain barrier. > 2. That the mercury from thimerosal is stored in the brain. That should answer Jeff's questions. > <snip> > [quoted text clipped - 33 lines] > cumulative, since they always seem to add up the total exposure. This says > that they were wrong/lieing. You can stop right there. This is why you took the article apart, which is what you call snipping for focus. Except the focus is what you left out. http://www.niaid.nih.gov/factsheets/thimerosalqa.htm NIAID-Supported Studies on Mercury, Thimerosal, and Vaccine Safety Overview Thimerosal is a preservative that has been added to some vaccines and other products because it is effective in killing bacteria and in preventing bacterial contamination. When thimerosal is degraded or metabolized, one product is ethyl mercury. In July 1999, U.S. Department of Health and Human Service (DHHS) agencies, including the National Institute of Allergy and Infectious Diseases (NIAID); The American Academy of Pediatrics; and vaccine manufacturers agreed that thimerosal should be reduced or eliminated in vaccines as a precautionary measure and to reduce exposure to mercury from all sources. This decision was based on the various Federal guidelines for methyl mercury exposure and the assumption that the health risks from methyl and ethyl mercury were the same. More research is needed to determine if the guidelines for methyl mercury are also appropriate guidelines for thimerosal. NIAID thimerosal research focuses on better understanding what happens to thimerosal once it is introduced in the body and how this compares to current knowledge of methyl mercury pathways. How does methyl mercury exposure differ from thimerosal exposure? There are important differences between methyl mercury exposure and thimerosal exposure. a.. Thimerosal contains ethyl mercury, which is structurally different from methyl mercury. b.. The timing and route of exposure are different for these two chemicals. People mainly become exposed to methyl mercury through eating fish. Some of this methyl mercury may be passed from the mother to the fetus before birth and to infants through breast milk. Prior to the removal of thimerosal from childhood recommended vaccines, infants were exposed to thimerosal by intramuscular injection during vaccination, not by ingestion. Furthermore, infants received thimerosal from vaccines that were administered days or months apart. In contrast, methyl mercury exposure, primarily from foods, tends to occur over a longer, sustained period of time. What is known about prenatal exposures to ethyl mercury? There is minimal modern research to address whether or not ethyl mercury may be passed from the mother to the fetus before birth. As a precaution, DHHS and product manufacturers are working to reduce or eliminate thimerosal from products that may be given to pregnant women, such as Rho (D) Immune Globulin. Also, thimerosal-free versions of several adult vaccines are available for use. Are the current mercury guidelines appropriate for assessing thimerosal exposure? Methyl mercury guidelines assess a child's risk based on a continuing daily mercury exposure. As mentioned above, there are several important differences between methyl mercury exposure and thimerosal exposure. More research is needed to determine if the guidelines for methyl mercury exposure are also appropriate guidelines for thimerosal. What research is NIAID funding to find out more about the effects of thimerosal exposure and how it compares with methyl mercury exposure? NIAID has supported several studies to address these questions, including a.. One completed study of mercury levels in infants who received vaccines containing thimerosal b.. Two follow-up studies of mercury levels in infants who receive vaccines containing thimerosal c.. One ongoing study of thimerosal and methyl mercury exposure in infant monkeys What was the purpose of the published study about thimerosal and vaccinations? NIAID-supported studies at the University of Rochester and National Naval Medical Center in Bethesda, MD, looked at levels of mercury in blood and other samples from 61 infants who had received routine immunizations with thimerosal-containing vaccines. What types of samples were assessed? Mercury levels were measured in blood, urine, and stool samples from infants at different times up to 28 days after vaccination. Researchers also looked at levels of mercury in samples of breast milk, mother's hair, and infant formula. What were the primary results obtained from assessment of these samples? a.. Blood levels of mercury were uniformly below safety guidelines for methyl mercury for all infants in this study. b.. Mercury was cleared from the blood in infants exposed to thimerosal faster than would be predicted for methyl mercury. c.. Infants excreted significant amounts of mercury in stool after thimerosal exposure, thus removing mercury from their bodies What can be concluded from the results of the Rochester study? These results suggest that there are differences in the way that thimerosal and methyl mercury are distributed, metabolized, and excreted. Thimerosal appears to be removed from the blood and body more rapidly than methyl mercury. Where can I find more information on the Rochester study? The results have been published in the November 30, 2002, issue of the scientific journal, The Lancet. Reference: Pichichero ME, Cernichiari E, Lopreiato J, and Treanor J. Mercury concentrations and metabolism in infants receiving vaccines containing thimerosal: a descriptive study. Lancet 360:1737-1741 (2002). The Lancet online: http://www.thelancet.com Does NIAID plan to support any further research to assess mercury levels in infants who received vaccines containing thimerosal? Yes. NIAID is supporting a follow-up study with a larger number of infants. The University of Rochester is collaborating with the Children's Hospital of Buenos Aires in Argentina to conduct this study. The Argentina clinicians are measuring mercury in blood and other samples from infants receiving routine vaccinations with thimerosal. NIAID also plans to conduct an additional study in Argentina that will focus on enrollment of premature (32 to 37 weeks gestational age) and low birth weight (2000 to <3000 grams) infants. Although some thimerosal-containing vaccines still are given to children in Argentina, most vaccines now given to children in the United States are either thimerosal-free or contain markedly reduced amounts of thimerosal. What does NIAID hope to learn from the follow-up studies of thimerosal and vaccines in infants? The goals of these studies are to assess the levels of mercury in the blood and other samples from infants receiving thimerosal-containing vaccines as part of their routine immunization schedule and to obtain more samples closer to the time of vaccination. What is the purpose of the ongoing studies of thimerosal and methyl mercury exposure in infant monkeys? NIAID is supporting studies in infant and adolescent monkeys to compare the distribution, metabolism, and clearance of mercury after exposure to thimerosal and methyl mercury. Infant monkeys were exposed to either thimerosal or methyl mercury on a weekly basis. Blood levels of mercury were determined for each animal after each exposure. The development and behavior of the monkeys has also been monitored. After the fourth dose, animal tissues were analyzed to determine levels of mercury in target tissues, such as brain and kidney. These studies will provide information to help determine whether or not the guidelines for methyl mercury are also appropriate for thimerosal. Are the results available for the ongoing studies of thimerosal and methyl mercury exposure in infant monkeys? Currently the investigators of this study are completing their analyses of the data obtained from this study. Preliminary results from these studies indicate a.. Mercury, in the form of methyl mercury (oral ingestion) and thimerosal (intramuscular injection with vaccines) were both readily absorbed and distributed into blood and brain. b.. Total (organic plus inorganic) mercury was cleared from both blood and brain faster after thimerosal exposure than after methyl mercury exposure. c.. Levels of total mercury measured in blood and in brain were lower after thimerosal exposure than after methyl mercury exposure. d.. The proportion of brain mercury that was inorganic was higher in animals exposed to thimerosal compared with methyl mercury. e.. The absolute amount of inorganic mercury was higher in thimerosal exposed animals compared with methyl mercury. f.. During weekly doses of methyl mercury, total mercury in blood continued to accumulate, while during weekly doses of thimerosal, there was little accumulation of total mercury in blood. This study indicates that methyl mercury is not a suitable reference for risk assessment from exposure to thimerosal. This study was not designed to measure any type of damage due to mercury exposure. The mechanisms by which organic mercury is converted to inorganic mercury in the brain are unknown. There is not a consensus as to whether inorganic mercury in brain causes damage or to what extent compared to organic mercury. These results were recently published in Environmental Health Perspectives. For more information, see http://ehp.niehs.nih.gov/docs/2005/7712/abstract.html. -------------------------------------------------------------------------------- NIAID is a component of the National Institutes of Health (NIH), which is an agency of the Department of Health and Human Services. NIAID supports basic and applied research to prevent, diagnose, and treat infectious and immune-mediated illnesses, including HIV/AIDS and other sexually transmitted diseases, illness from potential agents of bioterrorism, tuberculosis, malaria, autoimmune disorders, asthma and allergies. News releases, fact sheets and other NIAID-related materials are available on the NIAID Web site at http://www.niaid.nih.gov. Prepared by: Office of Communications and Public Liaison National Institute of Allergy and Infectious Diseases National Institutes of Health Bethesda, MD 20892 Nobody lied about anything, except you, in your quest to make it an error of *my* ways, which is ridiculous. and typical for you. LL/Jan >> b.. Mercury was cleared from the blood in infants exposed to thimerosal >> faster than would be predicted for methyl mercury. [quoted text clipped - 109 lines] >> Perspectives. For more information, see >> http://ehp.niehs.nih.gov/docs/2005/7712/abstract.html. >>>http://www.niaid.nih.gov/factsheets/thimerosalqa.htm >> [quoted text clipped - 6 lines] > > That should answer Jeff's questions. No, I made a simple statement of the issues addressed by the article. Do not read anything into my simple statement. >><snip> >> [quoted text clipped - 36 lines] > > You can stop right there. No, I cannot stop right there. YOU posted an article where I highlighted the fact that the ethyl mercury from thimerosal is rapidly cleared by infants, so that storage, like your anti-vac liar friends like to claim, is just not possible. YOU posted the article. I cleared out anything not directly relevant to what addressed the two points that you erroneously thought addressed Jeff. > This is why you took the article apart, which is what you call snipping for > focus. > > Except the focus is what you left out. No, the focus is EXACTLY what I left in. The fact is, this article disproves one of your pet claims, i.e., ethyl mercury from thimerosal is stored in the baby's brain. I have addressed this point numerous times in the past, and you have merely snipped away what I have posted. Now, when you posted, your are caught with your foot in your mouth, and do not like it. TOO BAD! You posted it, you live with it. BTW, the article cites the study that I always cite. Great minds think alike. I'll leave your complete repost in for those readers who may desire to see if my editing changed meaning. Of course, it did not. The fact is, toots, you cannot handle the fact that you disproved your own claim. BWHAHAHAHAHAHAHA! > http://www.niaid.nih.gov/factsheets/thimerosalqa.htm > [quoted text clipped - 309 lines] >>>Perspectives. For more information, see >>>http://ehp.niehs.nih.gov/docs/2005/7712/abstract.html. |
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