Blockbuster Primate Study Shows Significant Harm from One Birth Dose of a Mercury-Containing Vaccine
Posted Sep 30 2009 12:00am
[Editor's update: The article is now available for purchase at Science Direct. See link below.]
By Mark Blaxill
A research team led by scientists from the University of Pittsburgh and Thoughtful House reported today that exposure to a birth dose of a hepatitis B vaccine that included an ethyl mercury preservative caused significant delays in the development of several survival reflexes in male rhesus macaque monkeys. The findings were published on line today in the journal Neurotoxicology. [See the abstract below and the link to a site where you can purchase the article on Science Direct HERE]
In the first safety study of its kind of the hepatitis vaccine birth dose, the researchers showed that male macaques vaccinated at birth with a hepatitis B vaccine (HBV) took more than twice as long as unexposed macaques to acquire three standardized skills typically used to measure infant brain development. The thirteen vaccinated monkeys each received a dose of Merck’s Recombivax® hepatitis B vaccine to which a weight-adjusted amount of the ethyl mercury-containing vaccine preservative thimerosal had been added (each dose included 2 micrograms of ethyl mercury as opposed to the human infant dose of 12.5 micrograms). Seven unexposed monkeys received either a saline placebo injection or no shot at all.
Over a two week period following birth, the researchers examined the infant macaques daily for their ability to perform nine basic reflexes (four reflexes were tested in two ways, so the paper reports thirteen performance results). Three of nine reflexes showed significant delays in vaccinated macaques while two other reflexes were delayed and “approached significance.” As for the three significant reflexes, vaccinated macaques learned more slowly to: 1) turn their head in response to a brush on the cheek (the root reflex); 2) open their mouth in response to a brush on the forehead (the snout reflex); and 3) suck on a nipple placed in their mouth (the suck reflex).
Although the paper is carefully worded and the results reported modestly, these findings are certain to receive intense scrutiny. For while hepatitis B vaccines currently produced in the United States no longer contain thimerosal, the vast majority of American infants born during the 1990s received a vaccine formulation similar to the one the thirteen vaccinated macaques received. In addition, thimerosal-containing HBVs are still routinely administered to newborn infants in developing countries such as Brazil. Consequently, the finding that early exposure to potentially toxic vaccine formulations can cause significant neuro-developmental delays in primates has explosive implications for vaccine safety management. These implications go far beyond the domestic HBV program and raise concerns about HBV formulations sold abroad as well as the domestic influenza vaccine program. Most influenza vaccines, including the vaccines in the upcoming swine flu program, contain thimerosal and are routinely administered to pregnant women and infants.