Autism: Playing Politics with Vaccines

“The odds of finding a single factor that causes autism, whether genetic or environmental is zero.”

Alexander Kolevzon, MD, psychiatrist and leader of Experimental Therapy Program, Seaver Autism Center, Mt. Sinai Hospital, New York

"I am different, not less."

Temple Grandin, PhD, American scientist, author, and autism activist

Secretary of Health and Human Services Robert F. Kennedy, Jr. is a notorious antivaxxer who believes the vaccine preservative thimerosal, like the measles vaccine, causes autism. He recently handpicked the new members of Centers for Disease Control and Prevention (CDC)’s Advisory Committee on Immunization Practices (ACIP).

On June 25, 2025, the first meeting of the reconfigured ACIP took place. Included on the committee’s agenda was a vote on whether to approve a flu vaccine containing thimerosal. The newly “appointed” ACIP voted against approval. This came as no surprise to most of us in the medical community but was deeply disappointing as at his confirmation hearing, Kennedy had promised he would “follow the science.” And, the science backing the safety of thimerosal is overwhelming.

 My personal reaction to the committee’s vote is summed up in “ACIP’s Thimerosal Vote: The Committee Has Lost Its Value to Medicine,” an article by Dr. Amesh Adalja published on June 27, 2025 in MedPage Today. But as the controversial link between vaccines and autism is likely to resurface as long as RJK Jr. is around, it seemed to be a relevant topic for this week’s Germ Gems post.

A Brief Overview of Autism. Autism or Autism Spectrum Disorder (ASD) is a neurological and developmental disorder that affects the way a person interacts with others, as well as how they communicate, learn, and behave. Autistic people have persistent difficulties in social communication and social interaction, alongside restricted, repetitive patterns of behavior. These challenges seriously impact an autistic person’s daily functioning. 

The American Psychiatric Association’s Diagnostic and Statistical Manual of Mental Disorders (DSM-5) outlines the specific criteria for diagnosing ASD. (The term Asperger’s syndrome is no longer used as Asperger’s is now considered part of the ASD spectrum.) A team of qualified professionals, including developmental pediatricians, child neurologists, child psychiatrists or psychologists, is typically involved in making the diagnosis and management of ASD.

Autism rates have exploded in the last 30 years—they’ve increased roughly 60-fold. CDC reports show that ASD affects 1 in 31 children and is more common in boys than girls (ratio 3.4:1). ASD is also more prevalent among Asian/Pacific Islanders, Black, and Hispanic children than white children.

Elon Musk, climate activist, Greta Thunberg, and animal behaviorist Temple Grandin are among a number of famous people diagnosed with autism. And characters in recent movies such as, Raymond Babbitt in “Rain Man,” Arnie Grape in ”What’s Eating Gilbert Grape,” Woo Young-woo in “Extraordinary Attorney Woo,” and Astrid Nielsen in “Astrid et Raphaelle,” provide examples of how ASD affects behavior, in both negative as well as positive ways.

What causes ASD? ASD is an idiopathic disorder; its cause is unknown. This is not, however, for the lack of trying. A large number of highly talented researchers have dedicated their careers not only to finding the cause of ASD, but treatment modalities and preventive measures as well.

Determining the cause of autism is extremely complicated. Therefore, Secretary Kennedy’s announcement setting a deadline of September 2025 for his agency to determine the cause of ASD was met with enormous disbelief in the scientific community. The Secretary has since walked back that firm deadline, stating his agency will have someinformation by September, but solid information won’t be available until March 2026.

Mr. Kennedy may be unaware of or chose to ignore that solid information about the cause of autism already exists. (The research has been done.) This includes, but is not limited to, the following:

1. Genetic component. Most researchers agree there is a strong genetic component. (See, Dr. Wilson, F. Perry, “We Are Seeing More Autism, and It’s Mostly Genetic,” Medscape, April 21, 2025). But it isn’t just a single gene that’s involved. Rather, ASD is thought by some to be a polygenic disorder requiring multiple genetic factors to be manifest. Also, many investigators share the view that some environmental factor contributes to the disease. I find the studies linking the increase in ASD to air pollution (the tiny particles called PM 2.5) particularly relevant.

   
   

2.  Infectious agents, such as cytomegalovirus and influenza virus in pregnancy or early in life have been implicated in ASD. At this time, however, no single microbe stands out as a potential cause. Also, several studies suggest that an altered gut microbiome is playing a role, and fecal microbiota transplantation has been explored as a potential treatment for ASD.

   
   

3. Environmental factors that have been ruled out in the pathogenesis of ASD. Extensive studies and reviews have ruled out any involvement of the vaccine preservative thimerosal in ASD. Likewise, robust research over the past two decades, stemming back to Andrew Wakefield’s fraudulent study of the connection between measles vaccine and ASD published in The Lancet in 1998, have shown no bona fide association between vaccines and ASD.

   
   

4. Increased recognition. Dr. Allen Frances, Professor and Chairman Emeritus of the Department of Psychiatry and Behavioral Sciences at Duke University School of Medicine, is a psychiatrist who was involved in the revised DSM categorization of ASD to include Asperger’s syndrome. According to Dr. Frances, the burst in new cases of ASD over the past two decades is due in part to improved recognition but also to “over diagnosis,” the mislabeling of socially awkward behavior as autistic (See, Frances, A., “Autism Rates Have Increased 60-Fold. I Played a Role in That,” New York Times, June 23, 2025).

   
   

The Harm of RFK, Jr.’s Research Agenda. Recently, Emily Largent, PhD, commented on Mr. Kennedy’s research agenda. (See, Largent, E.,  “Autistic People Shouldn’t Be the Only Ones Worried by RFK Jr.’s Research Agenda,” MedPage Today, June 18, 2025). She wrote: “If you have autistic patients or an autistic person in your family, you should worry. Research can harm people not directly involved in it and should be conducted with attention to minimizing such harms…Kennedy’s hurtful comments have already perpetuated stigma…Across numerous well-done studies, no one has ever found any evidence of an autism-vaccine link…Further work on autism and vaccines will likely waste taxpayer dollars.”

The fallout from Kennedy’s dismissal of the CDC’s ACIP experts and his restructuring of the committee with antivaxxers is clear—vaccines are under attack. The antivax community is likely cheering the ACIP’s recent decision against use of thimerosal in vaccines even though the scientific evidence supports the safety of the preservative. (See, Harper, M., “Here is how we know that vaccines do not cause autism,” Medicine, February 3, 2025).

Given the extraordinary benefit of vaccines in saving us from fatal infections, anything that perpetuates anti-vaxx disinformation, is likely to result in reduced vaccine use and thereby to a waste of innocent human lives. Nonetheless, at the time of the writing of this Germ Gems post, there is no director or acting director of the CDC. And it appears that despite his lack of qualifications for the role, Secretary Kennedy is planning to lead this incredibly important American (if not global) public health institution. Therefore, physicians and public health officials need to look elsewhere for guidance of patients about vaccines. The question is, where?