Mr. and Mrs. V. brought their six-month-old child to the office for her well check. I noticed that Mrs. V. had a packet of articles with her, many of which looked like they had been downloaded from the Internet. After we discussed her daughter’s growth and development, and I had completed my exam, Mrs. V. informed me that they had decided NOT to give her any more immunizations. When I asked her why, thinking it was probably because of all the mis-information about vaccines and autism that had hit the airways recently, she informed me that they were concerned about the thimerosal in the vaccines. Clearly she had done her homework, and I commended her for diligently researching the matter. There have been many stories about this in the print and television media over the past few years.
Thimerosal is a compound that is derived from ethylmercury and has been widely used as an antimicrobial agent in biologicals and vaccines since the 1930’s. It is very effective in killing bacteria and preventing bacterial contamination, particularly in opened multi-dose containers. These are bottles of vaccines that contain multiple doses in a single bottle. Each time the nurse wants to administer a vaccine, she cleans the top of the vial with alcohol, then draws up a dose and gives it. Many of these vials will contain ten or so doses in each bottle.
In 1999, the Food and Drug Administration (FDA) became conerned about the amount of mercury that a child could be exposed to after receiving the standard immunizations of childhood. There is no doubt that mercury is very toxic to the central nervous system and to the kidneys. The main route of human exposure to mercury has been through consumption of contaminated food, especially fish. This type of mercury is in the form of methylmercury. The type of mercury that is in thimerosal is ethylmercury, which is felt to be less toxic to humans. It is metabilized and excreted much faster by the body. The only problem was that there were no standards for ethylmercury. Therefore, the FDA guidelines for the more harmful form that is found in food was all that the various agencies studying this had to go on.
What followed was a flurry of activity by numerous agencies that included the FDA, the EPA, the American Academy of Pediatrics, the American Academy of Family Practice, the Agency for Toxic Substances and Disease Registry, the CDC, the Interagency Vaccine Group and many others. They met in mid-1999 and could not reach a consensus about how to handle this. Even if a child received ALL the vaccines they were supposed to by six months of age, they would THEORETICALLY exceed the maximum level for methylmercury in the guidelines set by the EPA...but not the guidelines set by the FDA, WHO or the ATSDR. They were in a real quandary as to what to do. No question, the thimerosal had to be removed from the vaccines. But in the meantime what should they tell the public? One camp wanted to recommend that the hepatitis B vaccine not be given at birth unless it was documented that the mother had hepatitis herself. The problem with this was that not all hospitals were screening for this. A case study of an infant death from hepatitis B was cited during their discussions.
Another grave concern was the perception by the public, and the loss of confidence in the safety of the vaccines as well as loss of confidence of the agencies making the recommendations. In addition there was concern about how accurately the media would cover the matter. Each agency had strong feelings about their position and it was obvious that no one was going to bend. This prompted the Surgeon General to be brought into the negotiations. Finally a compromise was struck. The official statement was released on July 7, 1999 by the American Academy of Pediatrics and the Public Health Service. A goal was established to remove thimerosal as a preservative in vaccines that are routinely given to children as soon as possible. In the meantime, the hepatitis B vaccine schedule (which was to start at birth) would be delayed until a new vaccine that was thimerosal-free was available.
Much has changed since that summer of 1999. As of March 2000, all children had access to hepatitis B vaccines that were free of thimerosal as a preservative. We are now back to the schedule of safely immunizing newborns for this. Thimerosal has been removed from almost all of the childhood vaccines, due in part to the formulation of single dose vials.
As it stands now, all children can be fully immunized on schedule and not have to receive any vaccine that contains thimerosal. By 18 month of age, a child should have received: DtaP for diphtheria, pertussis and tetanus--4 shots; Polio--3 shots; HepatitisB--3 shots; Strep pneumonia--4 shots; MMR against measles, mumps and rubella--1 shot; and chicken pox--1 shot. All of these are now available without thimerosal. Of the three preparations of DtaP vaccines, one has a trace of thiomerosal in it, and the same is true for one of the two preparations available for hepatitis B.
Needless to say, Mrs. V. was relieved to hear this. After I showed them a reprint from the Center for Biologics Evaluation and Research that confirmed this information, she threw her stack of articles in the trash. “Let’s go for it! I was nervous about NOT having my daughter protected, but it was just so scary.”