Autism as a complication of vaccinations

In many developed countries, the issue of the link between autism and vaccination still dominates the media, reducing vaccination coverage and contributing to the persistence of measles cases.

In recent years, many countries have seen an increase (2-3 times) in the incidence of autism and other disorders of this spectrum (pervasive developmental disorders), the frequency of which has reached 0.6% of the child population. Research in 14 regions of the United States (more than 400,000 children) revealed prevalence rates of spectrum disorders of 0.66% with fluctuations from 0.33 to 1.06% and a predominance of boys in the ratio of 3.4-5.6 per 1 girl.

Most researchers associate this phenomenon with the expansion of the diagnostic framework of this pathology and the improvement of the diagnostic process. However, an article by Dr. Wakefield in 1998 linked the development of autism and chronic intestinal disorders in these children to the introduction of the MMR vaccine. This hypothesis, based on individual observations, was refuted by a number of carefully conducted studies that were summarized by two groups of scientists. In April 2008, the British Medical Council accused Dr. Wakefield of failure to comply with ethical standards in conducting his research and actions directed against the interests of the children being studied; he is currently not engaged in medical practice. Accusations have also been brought against his co-authors.

In the United States, in early 2008, the government granted a lawsuit filed by the parents of a 9-year-old child with mitochondrial disease and autism who had been vaccinated with MMR at 18 months, although it did not directly link the development of autism to the vaccination. This government action was condemned by the medical community.

It seems that the final word on this issue was put by two recently published studies. One of them studied the immune response to the measles vaccine in 98 10-12 year old children with autism compared with that in 148 children without autism. No difference in the immune response was found between the groups or between children with autism depending on the severity of symptoms. Measles virus RNA in peripheral blood monocytes was detected in 1 child with autism and in 2 in the comparison group.

Another study examined the presence of vaccine measles virus RNA in intestinal biopsies from children with intestinal disorders with and without autism. Blinded studies in three laboratories (including the one that initially proposed a link between lymphoid hyperplasia of the mucosa and autism with vaccination) found no differences between the experimental and control groups, or the timing of autism with the introduction of the vaccine.

Merthiolate, the sodium salt of ethylmercuric thiosalicylate, has been used for many years as an antibacterial preservative in various inactivated vaccines administered parenterally. In 1997, Congressman F. Pallone amended the law in the United States, requiring the FDA to study the issue of mercury preservative additives, including in vaccines. At a meeting in the United States in 1999, it was reported that a child under 6 months with 3 vaccinations (DPT, Hib, HBV) receives 187.5 mcg of mercury, which is small, for example, compared to the amounts of mercury received with some types of fish (in the form of methylmercury); moreover, not a single report of an adverse effect of merthiolate in vaccines has been identified. However, the meeting did adopt a “cautious” recommendation calling on manufacturers to consider reducing the dose of thimerosal in vaccines. Admittedly, this illogical conclusion has caused some concern; in particular, fewer children are being vaccinated against hepatitis B in the neonatal period, which is estimated to have exposed about 2,000 newborns a year to hepatitis infection due to errors in testing pregnant women.

In order to study the possible adverse effects of thimerosal in vaccines, studies appeared as early as 2004 that gave a negative answer to this question. Blood mercury levels in newborns, 2- and 6-month-old children were maximum during the first day after vaccination and were 5.0±1.3, 3.6±1.5 and 2.8±0.9 ng/ml, respectively; they quickly decreased and returned to the pre-vaccination level by the end of the month. Thimerosal was excreted in feces (19.1±11.8, 37.0±27.4 and 44.3±23.9 ng/g, respectively, with a maximum on the 5th day), and the half-life was 3.7 days. The authors conclude that the pharmacokinetics of thimerosal differ from those of methylmercury, so that data on the latter cannot be extrapolated to thimerosal.

The most comprehensive study was the one on psychomotor development in 42 parameters of more than 1,000 children aged 7-10 years. It showed that a higher dose of thimerosal, received with vaccines and immunoglobulin at the age of 0-7 months, was associated with higher (by 1 point) indicators of fine motor coordination, attention and independent activity. A higher dose of thimerosal at the age of 0-28 days was associated with a lower (by 1 point) ability of speech articulation, but with higher (also by 1 point) indicators of fine motor coordination.

And the reports about the connection between autism and thimerosal in vaccines seem completely implausible, despite the consistently negative results of a number of studies on this issue. Thus, in the USA in 2000-2001, the use of vaccines with thimerosal was practically stopped, however, in the following years, an increase in the number of autistic patients who did not receive thimerosal was noted. An analysis of the data on this topic revealed serious methodological errors; no connection between thimerosal in vaccines and autism was found. And because of sensational reports in the media, fears are maintained among the population and chelation therapy of autistic children (about 10,000 in the USA) is stimulated, which not only has no proven effectiveness, but can also be deadly.

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