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An anti-vaccine movement that has been amplified by the Internet and endorsed by vocal celebrities has created a persistent public fear that the measles-mumps-rubella (MMR) vaccine causes autism in children.
As a result, some parents are avoiding MMR immunization of their children, joining other groups that reject the vaccine out of religious or personal beliefs. Unvaccinated travelers to areas of measles outbreaks (e.g., the Philippines) can bring the highly contagious disease home, where transmission may explode in one of these groups that has rejected immunization.
The Immunization Action Coalition (IAC) in Saint Paul, MI, a group that is funded by and affiliated with the Centers for Disease Control and Prevention, states the following: "There is no scientific evidence that measles, MMR, or any other vaccine causes autism. The question about a possible link between MMR vaccine and autism has been extensively reviewed by independent groups of experts in the U.S. including the National Academy of Sciences’ Institute of Medicine. These reviews have concluded that there is no association between MMR vaccine and autism."1
Recent estimates from the CDC’s Autism Developmental Disabilities Monitoring network found that about 1 in 68 children born in 2002 have autism spectrum disorders. This estimate is higher than estimates from the early 1990s, the CDC reports.2
"Over the years, some people have had concerns that autism might be linked to the vaccines children receive," the CDC states. "One vaccine ingredient that has been studied specifically is thimerosal, previously used as a preservative in many recommended childhood vaccines. However, in 2001 thimerosal was removed or reduced to trace amounts in all childhood vaccines except for one type of influenza vaccine, and thimerosal-free alternatives are available for influenza vaccine. Evidence from several studies examining trends in vaccine use and changes in autism frequency does not support such an association between thimerosal and autism."
Indeed, the fact that autism has increased after thimerosal was largely removed from vaccines has led one study to conclude that the "increased prevalence of autism may be attributable to improved diagnostic criteria and increased awareness of autism."3
Though there have been concerns about various vaccines since the era of immunizations began, the current controversy linking autism to MMR vaccine can be traced to a 1998 paper in the British journal The Lancet that was subsequently retracted.4 In retracting the article in 2010, the journal stated that "claims in the original paper that children were consecutively referred’ and that investigations were approved’ by the local ethics committee have been proven to be false. Therefore we fully retract this paper from the published record."5
Nevertheless, the damage done continues to echo on the Internet, where concerned parents may find a wealth of misinformation circulated by anti-vaccine groups.
Paul Offit, MD, a vaccine researcher and chief of the infectious disease department at Children’s Hospital of Philadelphia, has led the fight against the growing anti-vaccine movement. He says the retracted Lancet paper "gave birth to the general idea that vaccines could cause autism. I think that will not go away until we know what the real cause or causes of autism are."
In the interim, Offit warns that childhood diseases could become reestablished and even polio could return through imported cases.
"We’ve seen outbreaks of pertussis," he says. "I think there’s every reason to believe that you could see diseases like polio come back in the United States. It is certainly in the world, and international travel is common."
In his book, "Deadly Choices: How the Anti-Vaccine Movement Threatens us All," Offit offers a sobering reminder of the pre-vaccine era:
"In the early 1900s children routinely suffered and died from diseases now easily prevented by vaccines. Americans could expect that every year diphtheria would kill 12,000 people, mostly young children; rubella, (German measles) would cause as many as 20,000 babies to be born blind, deaf or mentally disabled. Polio would permanently paralyze 15,000 children and kill 1,000, and mumps would be a common cause of deafness. Because of vaccines all of these disease have been completely or virtually eliminated. But now because more and more parents are choosing not to vaccinate their children some of these diseases are coming back."6