April 27, 2010 15:21
Because there have been many posts relating stories about children who regressed after receiving their vaccines, I would like to address what the community of clinical autism specialists have come to believe, based on many years of observation and analysis of children on the spectrum.
Autism is largely believed to be a biologically based neurodevelopmental disorder, which in most cases means a child will or will not develop autistic features based on their biology at birth and their genetic heritage.
A developmental regression is a very alarming thing to see. Pediatric residents are taught to ask about it and look for it in very young children because it often represents something truly awful, like a genetic syndrome with a poor prognosis, or a serious underlying medical condition. I recently saw a 10 month-old boy who had been happily pulling up to stand for a month and suddenly stopped. He had a serious bacterial infection in the vertebra of his spine, for which he was hospitalized and treated, and completely recovered.
There have been a number of fascinating studies of children diagnosed with autism who were felt who have undergone a developmental regression. About a quarter of parents of autistic children report that their child had a regression of development. Many experts believe that regression is simply part of the process for many cases of autism. When first birthday videos made by families were reviewed with expert eyes -- but blinded to which children were ultimately diagnosed -- there were indications that those children had early, though often subtle, indications of developmental differences.
Similarly, infant sibling studies which are following the younger siblings of children already identified as autistic, demonstrate that some signs are evident to experts as early as six months of age. So while we may think the child has regressed, it isn't always the case.
The reason the infant sibling studies are so critical is because of the recurrence rates in families. When asked by parents with one child what the likelihood is that a second child would be affected, we generally quote about a 6-8% recurrence rate. Among identical twins both are affected about 90% of the time. I always suggest genetic testing if couples are considering having another child, and follow a good number of families with multiple affected children (some vaccinated and some not, in a few families), as well as some families where a gene was unexpectedly identified as the culprit.
I have certainly received calls from parents about babies screaming or having high fevers after their vaccines. In those cases, we carefully plan out how to administer the rest of the series. In my practice we have not seen dramatic negative outcomes with long term significance in any of our patients. Babies do have medical problems sometimes. Babies can have seizures, babies can get and do get fevers. Sometimes it's simply impossible to know if a baby with a fever or a seizure shortly after a vaccine may have had the fever or seizure without the vaccine.
I hope this helps to answer how we think about some of these important and difficult questions. I am deeply indebted to the parents of autistic children for helping us investigate the causes of the autism spectrum disorders. I am including a few links to studies of interest:
Adrien JL, Lenoir P, Martineau J, et al. Blind Ratings of Early Symptoms of Autism Based Upon Family Home Movies. J Am Acad Child Adolesc Psychiatry 1993; 32:617-626.
Adrien JL, Perrot A, Sauvage D, et al. Early Symptoms in Autism From Family Home Movies: Evaluation and Comparison Between 1st and 2nd Year of Life Using I.B.S.E. Scale. Acta Paedopsychiatrica 1992; 55:71-75.
S. J. Spence, "The Genetics of Autism," Seminars in Pediatric Neurology 11
R. Muhle, S. V. Trentacoste, and I. Rapin, "The Genetics of Autism," Pediatrics
113 (2004): 472-86;
M. T. Miller, K. Strömland, L. Ventura et al., "Autism Associated with
Conditions Characterized by Developmental Errors in Early Embryogenesis: A Mini
Review," International Journal of Developmental Neuroscience 23 (2005): 201-19.