Immunization vs Incidence of Autism - Coursework Example

Running Head: IMMUNIZATION VS INCIDENCE Immunization vs Incidence in Autism Brian Hasse Hardin Simmons Patty Hanks Shelton School of Nursing Bachelor of Science in Nursing Program NURS ????/?? – ??? C. Northrup, Instructor December 6, 2008 Introduction The apparent increasing incidence of autism makes this topic a very important one. Autism itself has been a baffling condition for many years. Diagnosing it and identifying the causes have been equally challenging. Nevertheless, many young children, and now even adults, are struggling to fit into society and function normally with this disorder. Like any other disorder that interferes with a human’s quality of life, the medical community is concerned with finding, if not a cure, then the interventions to manage this disorder. In order to find a cure or to develop management strategies, it is important that all the factors contributing to the disorder be identified. Immunization is one of the factors that have been implicated in the incidence of autism. Since 1999 there has been a controversy about whether thimerosal–containing vaccines contribute to the causes of Autism Spectrum Disorders (ASDs) and neuro-developmental disorders (NDDs) in children. Autism affects not only the children living with the condition but the families of these children. Some siblings have to learn how to cope with a brother or sister who is autistic. It is of great importance to parents and has caused many parents to question the safety of immunizing their children. Several parents have refrained from immunizing their children against common childhood diseases. This has caused conflicts in schools where immunization is a requirement of a young child entering school. It is important therefore to understand as much as we can about this disorder and whether there is in fact a connection between vaccination and the disorder. Purpose of Paper The purpose of this paper is to explore the relationship between the Autism Spectrum Disorder spectrum and immunization. The paper seeks to review the research evidence provided on both sides of the debate. Does the immunization of a child in fact increase the possibility of developing autism or is there no relationship between the chemicals in childhood immunizations, e.g. thimerosal and autism? It is important to try to determine how valid and reliable the research studies are. Parents need to be reliably informed about the consequences and possible dangers of immunizing their children. The analysis of the topic could help them in their decision about whether to immunize or not. An initial examination of the topic could help in the weighing up of the pros and cons of immunization against the possibility of the child being vulnerable to developing the autism disorder or any other neuro-developmental disorder. It is sometimes difficult to obtain balanced information representing both sides of a debate. This analysis of the issue aims to present research and thinking of experts on both sides of the coin. An attempt will be made to present as much of the valid information as possible that will help in determining whether or not immunization is a contributing factor in the incidence of autism. Literature Review The indication of a connection between autism and vaccines was first discussed by Andrew Wakefield in 1998 when he published a paper in the prestigious journal Lancet which claimed that eight out of twelve children developed Autistic Spectrum Disorder and bowel symptoms days after being immunized (Taylor, 2006). This study was subsequently challenged for a number of reasons. The idea was later raised that there could be a number of other factors accompanying what seemed to be the onset of autism following immunization. It was difficult to determine if any of these factors themselves could not be contributing to behavior disorders resembling autism. Taylor presents all the different types of evidence that have been presented to show a relationship between vaccinations and autism, but he also presents the reasons for refuting this evidence. Parker et al (2008) systematically analyzed twelve published studies from Denmark, Sweden, UK and US in an attempt to clear up some of the confusion about the possible link between thimerosal and autism. They did a thorough literature search and analyzed all research studies published between 1996 and 2004 that evaluated an association between vaccines and autism spectrum disorders and neuro-developmental disorders. Some of the literature reviewed by the authors indicated that in 2001 thimerosal in quantities sufficient to act as a preservative was removed from all vaccines in the childhood immunization schedule in the US except in some influenza vaccines. There was also information that stated that although trace amounts are present in some vaccines, “the amounts are so small that exposure is inconsequential”. The Immunization Safety Review Committee of the Institute of Medicine concluded in 2001 that “the evidence is insufficient to accept or reject a causal relationship between exposure to thimerosal and NDDs”. In order to examine this claim more fully the authors analyzed the twelve studies. They found only four studies of the twelve supporting a link between vaccination and autism. They concluded that “the four studies supporting an association between thimerosal exposure and NDDs including autism were by the same authors and used overlapping data sets and contained critical methodological flaws that render the data and their interpretation non contributory”. On the other hand, they found that the studies that did not report an association were well designed and appropriately analyzed. In addition to inconclusive evidence in these papers of any definite link between vaccinations and autism, they also make the point that data from Denmark and Sweden where exposure to thimerosal in vaccines was eliminated in 1992 showed that rates of autism continued to increase. This finding, therefore, questions thimerosal as a possible contributing cause to autism. The Public Health Agency of Canada also supports the hypothesis that thimerosal does not cause autism or other neuro-developmental disorders. In the paper, Thimerosal –updated statement ( Law and Primeau , 2007) the authors reported two reviews of the evidence by the Immunization Safety Review Committee of the US Institute of Medicine (IOM) in 2001 and 2004 . In 2001 they concluded that "the evidence is inadequate to accept or reject a causal relationship between thimerosal exposures from childhood vaccines and neuro-developmental disorders. They also believed that “the hypothesis that thimerosal exposure through the recommended childhood immunization schedule [in the US] has caused neuro-developmental disorders is not supported by clinical or experimental evidence." The subsequent review in 2004, which included studies from Denmark, Great Britain, Sweden and the US, concluded that "the evidence favors rejection of a causal relationship between thimerosal containing vaccines and autism." The paper also reported Canadian data from a study in Quebec of 188 children to support the lack of association between thimerosal exposure and pervasive developmental disorders (PDDs). Despite the belief that thimerosal exposure has not been scientifically proven to be linked to autism, the Public Health Agency states that in large concentrations over extended periods of exposure, mercury can cause damage to brain and kidney. However, the amount of mercury -based product in a dose of vaccine can in no way be considered large concentrations over extended periods of time. Nelson and Bauman (2003) examined the claim that there is a link between thimerosal and autism from three different angles. The first was a claim that there were similarities in children with mercury poisoning and autism. They found no commonality in motor manifestations. The only common motor manifestation they found was in repetitive behavior such as rocking or flapping. Other signs such as hypertension, skin eruptions evident in mercury toxicity were not present in autism. They concluded that the “typical clinical signs of mecurism are not similar to the typical clinical signs of autism”. The second angle was to look at the onset of autism after immunizations. According to them the onset is very difficult to establish and age of onset is misleading as to the effect of the environmental factors. They therefore find the evidence from this angle to determine the role of vaccines in autism inconclusive. Thirdly, they questioned the existence of mercury levels in autistic children. No evidence was provided to show significant amounts of mercury in the hair, urine, or blood of autistic children. The authors also pointed out that they found no literature reports of such. They also point out that no evidence has been provided to show that chelation therapy led to the improvement in children with autism. Another issue raised by theses authors is the fact that mercury has been in the environment for ages. In the first half of the 20th century medicines containing mercury were used to treat various diseases. And even though some children treated with these mercury-containing medicines did in fact suffer from other symptoms, none of them were diagnosed as behavioral symptoms of autism. Another point raised by these authors is the question of whether reducing levels of mercury can affect the levels of incidence of autism. They referred to a study done in Japan during and after a toxic outbreak in the 1950s and the 1960s. The results showed on the contrary, higher rates of autism in children born between 1966 and 1974 than in the periods just after the outbreaks. This can be compared on a global scale, where in fact mercury-containing substances are more controlled, yet the level of autism is rising in most parts of the world. Rationale Autism remains a baffling disorder to many. Identifying the causes and diagnosing it still present challenges. Therefore it is important to continue the research and exploration in order to find answers. From the literature it is clear that there is much confusion about the disorder. There have been many researchers trying to prove different causations and relationships with this disorder, perhaps some of which is not provable. For these and other reasons, it is difficult to establish actual figures for the incidence of autism in any community or perhaps country. It is believed that the incidence is on the rise. The Autism Society (2008) reports that in “February 2007, the Centers for Disease Control and Prevention concluded that the prevalence of autism had risen to 1 in every 150 American children, and almost 1 in 94 boys”. Although these figures are alarming, there is controversy about even this. There is question about whether this increase is due to an actual rise in the incidence, or a rise in the diagnosis. Perhaps more people recognizing the symptoms in their children and coming forth. Some may even question whether it is an improvement in the recognition of the symptoms, or a change in diagnosis from what would have earlier been described as mental retardation. Others may suggest that parents are coming forward with their children as better social and educational services are offered for autistic children. One of the questions that still remain largely unanswered and needs further research lies in the fact that more boys are diagnosed with autism than girls. Whatever the reason, the rise in incidence indicates the need for continuing research and answers to the many questions. Reflection The major factors proposed as contributing to the occurrence of autism are genetic factors and prenatal and postnatal environmental factors. Vaccines, particularly for measles, mumps and rubella have also been indicated as possible contributory factors. Thimerosal in particular has been named as the major chemical causing the problem. Thimerosal is a mercury-based preservative used to manufacture multidose vaccines as it helps to prevent the growth of bacteria and fungi and so can protect the immunized from infections at the site of the immunization. It was difficult to understand why this was considered such a risk. However it turned out that thimerosal contains ethylmercury and not methylmercury. This was the problem because in the US there were no guidelines for the safe amount of ethylmercury in the human body, the guidelines for methylmercury were used. This caused a problem since the assumption that the body handles both ethylmercury and methylmecury in the same way is false. The amount of ethylmercury used in the vaccines is considered within the safe levels for the human body. It was also interesting to read that when thimerosal was removed from vaccines there was no appreciable effect on the incidences of autism. There are many questions still to be answered. The information particularly on the causes of autism is so limited. One other concern is that if there are genetic implications in the cause of autism, how is that to be determined? There was no reliable data showing the incidence of autism in families or implicating a passing down of the disorder. The rising incidence of autism is also of concern. If it is that this is because of better diagnosis and more public awareness, then that may be a good thing in some way. Perhaps the scare of immunization causing autism had the benefit of raising awareness of autism. Despite the need for further research it will be difficult to set this up. It is perhaps unethical to vaccinate some children with vaccines containing thimerosal and others without and look for symptoms of autism. There are other challenges with such research. One is seen in the symptoms of autism which are so varied and sometimes inconclusive. “Children with some symptoms of autism, but not enough to be diagnosed with classical autism, are often diagnosed with PDD-NOS.  Children with autistic behaviors but well-developed language skills are often diagnosed with Asperger syndrome.  Children who develop normally and then suddenly deteriorate between the ages of 3 to 10 years and show marked autistic behaviors may be diagnosed with childhood disintegrative disorder.  Girls with autistic symptoms may be suffering from Rett syndrome, a sex-linked genetic disorder characterized by social withdrawal, regressed language skills, and hand wringing” (National Institute of Neurological Disorders and Stroke). How will the researches identify the disorder, and how long after vaccination will the diagnosis be made? There are so many other factors in the child’s environment that could affect behavior that it is also a challenge to reliably conclude that a vaccination is the cause of such a disorder. Although many studies have been done to prove or disprove the connection between vaccinations and autism, one question that arises out of the research relates to the use of the vaccine for many years. For example, the vaccine has been in use at least since 1970 in Denmark and was discontinued in 1992. Although they have attempted to analysis data from their registry, it makes one wonder how many children were in fact vaccinated between 1970 and 1992 with thimerosal, and of this obviously large number how many actually have been diagnosed with autism. Would the number justify a connection between the vaccination and the incidence of autism? The fact that mercury has been in the environment for so many years and is only now being implicated in the incidence of autism makes one think about the environment on the whole and the work that needs to be done to remove toxic chemicals safely. Whether or not mercury and vaccines are directly linked to such disorders as autism, the fact that the issue has been raised and had to be researched indicates some measure of concern for the toxicity of the environment. Perhaps this issue should emphasize the importance of research into other causes of the toxic materials in the environment, and on the other side of the issue, into other disorders and possible causes. References Law, B., & Primeau, M. (2007). Thimerosal:updated statement. Canada Communicable Disease Report. Vol.33. Retrieved August 25, 2008. http://www.phac-aspc.gc.ca/publicat/ccdr-rmtc/07vol33/acs-06/index_e.html Nelson, K.B., & Bauman, M.L. (2003). Thimerosal and autism. Pediatrics. 111 (3) pp.674-679. Parker, S., Schwartz, B., Todd, J., & Pickering, L. (2004). Thimerosal-containing vaccines and autistic spectrum disorder: a critical review of the published original data. Pediatrics. 114, (3), pp.793-804. Taylor, B. (2006) Vaccines and the changing epidemiology of autism. Child: Care, Health & Development. Vol.32 (5), pp.511-519. The Autism Society of America (2008) About Autism. Retrieved 8th November, 2008 http://www.autism-society.org/site/PageServer?pagename=about_home Read More