The CDC is planning a large study looking into potential connections between vaccines and autism, two sources told Reuters, despite significant research showing vaccines and autism are not linked.
The move comes during one of the largest measles outbreaks in the past decade, with two deaths in Texas and New Mexico. In Texas, 198 cases have been identified since late January, and 23 patients have been hospitalized.
It’s unclear whether HHS Secretary Robert F. Kennedy Jr., who has long promoted anti-vaccine views, is involved in the planned CDC study or how it would be carried out, Reuters said.
Kennedy has misstated key facts about the current measles outbreak and has promoted vitamin A as a measles treatment instead of emphasizing vaccines. He recently published an opinion piece for Fox News that said vaccination was a personal choice and urged parents to consult with their physicians.
Since at least 2014, President Donald Trump also has floated a theory that vaccines are behind the rise in autism cases, but no evidence indicates this is true.
Vaccines were first blamed in 1998, when Andrew Wakefield, MBBS, formerly of the Royal Free Hospital and School of Medicine in London, published a now-retracted paper in The Lancet stating that 12 children had intestinal abnormalities after receiving the measles, mumps, and rubella (MMR) vaccination. For eight of the 12 children, parents linked the onset of behavioral symptoms to the vaccine.
Wakefield and co-authors hypothesized that intestinal inflammation after the MMR vaccine released gut proteins that eventually migrated to the brain, causing damage that was reflected in autism symptoms.
“The Wakefield study was flawed because nothing was studied,” Paul Offit, MD, of the Children’s Hospital of Philadelphia, told MedPage Today in an interview earlier this year.
“It was merely a report of eight children who had developed signs and symptoms of autism within a month of receiving the MMR vaccine. There was not a control group,” he emphasized. “Therefore, there was no way of knowing whether autism was occurring at a level greater than would be expected by chance alone.”
In 1999, another group of London-based researchers found no epidemiological evidence for a causal association between autism and the MMR vaccine. That conclusion was played out repeatedly in studies published in subsequent years. One of the largest was a retrospective analysis of more than 537,000 children in Denmark, which showed the risk of autism diagnosis was similar between those who received the MMR vaccine and those who did not.
Other hypotheses linking autism and vaccines that have been debunked centered around thimerosal, a preservative used in some multidose vials of vaccines, and arguments claiming that administering multiple vaccines at once may weaken the immune system. All vaccines routinely recommended for children ages 6 years and younger in the U.S. are available in formulations without thimerosal, according to the FDA.
In the past two decades, autism diagnoses among children in the U.S. have jumped fourfold, according to CDC data. Several factors may have fueled the rising prevalence numbers, including a changing definition of autism, better awareness and ascertainment, and increased screening and surveillance. While the cause of autism is unknown, some research suggests environmental factors may interact with genetic predisposition to raise autism risk.
The CDC and HHS were not immediately available for comment, according to Reuters.
Please enable JavaScript to view the