In 1998 Andrew Wakefield, a British physician, published a report linking receiving the MMR vaccine (mumps, measles and rubella) with an increased risk of autism. Despite the fact that this report was later withdrawn by the publishing journal (The Lancet), and investigations demonstrated that Wakefield had had conflicts of interest and had been guilty of fraud (and lost his medical license), the suspicion about vaccines took hold of many parents. And in spite of the fact that later studies have also disproved this connection, fear remains in some quarters and is linked to a distrust of vaccines and a decrease in the vaccination rate. Thus it is important to pay attention to yet one more study of the purported connection between MMR vaccination and autism spectrum disorders (ASD).
Dr. Anjali Jain of The Lewin Group, a healthcare consulting group in Falls Church VA, and colleagues studied approximately 95,000 children to see if there was any evidence of a link between MMR and ASD. They examined children who did or did not have an older sibling who had been diagnosed with ASD. In addition, they evaluated the risk of an ASD diagnosis in children who had or had not received the MMR vaccine. Of concern was the possibility that parents who had one child diagnosed with ASD might be less likely to vaccinate younger children.
The researchers found that a higher percentage (about 7 percent) of children with an older sibling affected by ASD also had ASD diagnoses, while less than 1 percent of those with siblings without ASD were thus diagnosed. Further, the MMR vaccination rates for children with an ASD-affected sib were indeed less than for those with an unaffected older sibling 73 versus 84 percent, respectively. Importantly, receipt of the MMR vaccine was not associated with an increased risk of ASD whether or not the child had an affected older sibling.
Such studies are of public health importance because in some areas of the United States, parents are opting out of vaccinations for their children based on fear of ASD or other ills. In many cases, they have used philosophical bases for refusing vaccinations of many sorts. Thus, as we have reported, we have seen large outbreaks of measles in areas where vaccine deniers live, such as southern California. This has become so problematic that California is considering a bill to eliminate exemptions based on a parent s personal belief, as recently discussed in a NY Times editorial. The bill is currently in committee in the state legislature, which will rule on it on April 22.
ACSH s Dr. Ruth Kava commented: It s truly exasperating that many parents are ignoring the science about vaccines. This study, once again, found no link between MMR vaccination and autism, even in children who had a sibling diagnosed with the condition and thus could be assumed to be at higher risk than those without such a sibling. So it should be clear that children in general will not be more prone to develop ASD just because they receive the MMR, or any other vaccine. We must keep the vaccination rate up for all children to prevent future outbreaks of infectious diseases and protect the general public health.