At present, there is no evidence to suggest that there are any additional safety issues around thimerosal-containing vaccines for the HIV positive patient as compared to others. Here, a look at the leading research, which has been done on non-HIV infected individuals.
What Is Thimerosal Exactly?
Thimerosal is a mercury-containing preservative that has been used in vaccines and other products since the 1930s to prevent bacterial or fungal growth during vaccine production. In addition, thimerosal was used in vaccines to prevent bacterial and fungal contamination of multidose vials that occur after repeated puncturing of the vial's rubber seal.The need for such a preservative is rooted in a tragic event that occurred in Australia in 1928. In an attempt to vaccinate children against the deadly disease diphtheria, Dr. Ewing George Thomson, Medical Officer of Health of Bundaberg, used a multidose vial on 4 successive days to vaccinate 21 children. None of those children showed any ill effects after being vaccinated. The same vial was used to vaccinate another 21 children 4 days later. Of those 21 children, 12 died several days later by what was later determined to be due to staphylococcus contamination of the vial. From that event, it was mandated that if multidose vials were to be used for any biological product, it must contain a preservative to prevent microbe contamination.
Thimerosal became that preservative.
So What Is the Issue With Thimerosal?
Thimerosal is about 50% mercury by weight. Mercury and its byproducts are known to be neurotoxic, meaning they can result in serious neurological affects on the human body in certain concentrations and quantities. In fact, there are documented cases of mercury induced neurotoxicity.The first was found in Minimata Bay, Japan. The bay was found to be a dump site of industrial waste containing mercury. Scores of Japanese citizens in the area showed symptoms of neurotoxicity after eating fish from the bay. Another documented case occurred in Iraq in the 1970s. Grain treated with a mercury containing fungicide was accidentally used to make bread, resulting in cases of neurotoxicity after eating that bread.
Because of the documented fact that mercury toxicity does cause illness, experts and lay people alike question the use of mercury containing thimerosal in vaccines. In one example, experts have expressed concerns that infants may not be able to rid the body of mercury even in the smallest amounts found, thus making thimerosal use in infants suspect.
So What's Being Done About Thimerosal?
The FDA Modernization Act (FDAMA) of 1997 established investigations of the effects of mercury containing preservatives in vaccines. In 1999, investigators determined that the amount of mercury present in childhood vaccines was within acceptable limits, meaning that the amount of mercury a child receives when getting a vaccine is minimal. They also found that outside of localized injection site reactions, the amount of mercury received when vaccinated did not cause any neurological problems. Still, as a matter of caution, vaccine manufacturers have changed production methods, removing all but scant amounts of thimerosal from their vaccines. A thimerosal-free influenza vaccine is available in single dose syringes.Since 2001, all vaccines recommended for children 6 years old and younger are available with no or minimal amounts of thimerosal.
Thimerosal, Vaccines, and the Occurrence of Autism
There have long been concerns that there is a connection between vaccination, thimerosal, and autism. The concern is that even scant amounts of thimerosal can lead to the development of autism. On a number of occasions, these concerns of a causal relationship between vaccination, thimerosal, and autism have been investigated. Just about every expert scientific group including the Institutes of Medicine, the Centers for Disease Control, the American Academy of Pediatrics, and the American Medical Association have concluded that there is an overwhelming body of evidence that demonstrates no relationship between thimerosal in vaccines and autism.
What Should You Do About Thimerosal?
Many of the patients I work with have expressed concerns about being vaccinated against influenza and other preventable diseases. Some have cited preservatives and thimerosal as the reason they do not accept their vaccinations. Though this research is largely centered on young people, again, it is largely accepted that there is no evidence to suggest that there are any additional concerns for adults.If you have concerns about vaccines containing preservatives, namely thimerosal, speak with your HIV specialist about the availability of preservative-free vaccines. Most are available without preservatives and thimerosal, allowing you to get important vaccinations without worrying about potential problems associated and allegedly associated with the preservative thimerosal.
However, when considering a vaccination, weigh the risks of vaccine preservatives versus contracting the disease the vaccination prevents. In every case you will find that the health benefits of vaccination greatly outweigh the minimal risk associated with thimerosal. Science has proven that vaccinations are safe with or without thimerosal. Don't let the availability of thimerosal-free vaccines affect your decision to be vaccinated.
Sources
Centers for Disease Control and Prevention; "Mercury and Vaccines (Thimerosal)"; 8 Feb 2008.
United States Food and Drug Administration; "Vaccines, Blood and Biologics"; 31 Aug 2009.
United States Food and Drug Administration; "Thimerosal in Vaccines: Questions and Answers"; 10 July 2009.
