Dec. 7, 2025, 9:19 a.m. PT
The nation’s reliance on the CDC as the “ultimate authority” has always left me with a nagging concern: What happens if the CDC gets taken over by those who do not understand science?
That question is no longer a hypothetical one. We are witnessing what happens. On Nov. 19, the CDC changed its statement about the relationship between vaccines and autism.
Which brings me to a second concern: What kind of evidence would Robert Kennedy Jr., in his capacity as HHS director, rely upon to make claims about a connection between them?
The “evidence” is nothing short of comical and nowhere in the realm of science.
Let’s start with one of the two statements on the “new” CDC website: “Studies supporting a link [between autism and vaccines] have been ignored by health authorities.”
According to the “new” website, three cross-sectional studies provide “evidence” supporting a link between vaccines and autism. Cross-sectional studies look at variables at a single moment in time. It is impossible for a cross-sectional study to support or refute links between anything.
The most outrageous study is the first one. Seventy-four parents at two private clinics were polled about their “beliefs” about vaccines causing autism in their children. On what were they basing their opinion? The study does not tell us.
While no one knows what causes autism, 54% of the parents surveyed believe vaccines caused their child’s autism, even though 20% of the children in the study never received any vaccinations at all. This is not a scientific study; it is more like a Gallup poll.
The second cross sectional study looks at parental diagnosis of autism and hepatitis B vaccination. This study, which “met criteria for reliability,” shows that children vaccinated with Hepatitis B during the first month of life are three times more likely to have parents who believe their children have autism. The parents should have been asked if they believed a cow can jump over the moon, but sadly, that was not a question on the survey.
If you are a bit confused about what constitutes science, you are not alone, so is the “new” CDC.
It is important that the American public understands to show a “link” between two things, a study must be designed to evaluate cause-and-effect. A cross-sectional study can’t do that, but a cohort study can.
Let’s imagine that fathers of children with autism are surveyed about their gardening habits. Results show that children with autism are more likely to have fathers who mow lawns on Tuesdays. It is possible that gardening days are related to the risk of autism, but it is equally possible those two things are completely unrelated.
A cohort study would look at exposure over time (mowing the lawn on multiple Tuesdays) in comparison with a specific outcome (a medical diagnosis of autism.) The study would enroll children with and without autism and then inquire about the days their father mowed the lawn.
Let’s say the first study of 100 children shows Tuesday lawn mowing by dads is 10 times more common in children with autism. This result could still be due to random chances. Therefore, a larger study must be done. The next group would include 50,000 children, then 500,000 children, and then 1.5 million children.
That is the scientific process. There are no shortcuts. Cross-sectional studies cannot do the work of a cohort study.
Here is what cohort studies show us about the “link” between vaccines and autism, there is no cause-and-effect relationship.
- A 2002 Danish study with 537,000 children found no difference in autism risk between vaccinated and unvaccinated children.
- A 2019 Danish study of 650,000 children found the autism risk in vaccinated children compared to unvaccinated children was the same.
- A 2014 meta-analysis study of 1.5 million children found no connection between vaccinations and autism.
- And a 2021 review by Cochrane of 138 studies involving more than 23 million children, found no link between autism and MMR (mumps-measles-rubella) or MMRV (mumps-measles-rubella-varicella) vaccines.
The “new” CDC states: “The claim ‘vaccines do not cause autism’ is not an evidence-based claim because studies have not ruled out the possibility that infant vaccines cause autism.”
The statement “vaccines do not cause autism” is, indeed, evidence based. It is the best evidence we have gathered over decades across multiple countries throughout the world.
The “new” CDC is manipulating the evidence to confuse you. Instead of showing you the scientific process, they are snowing you with parental opinions masquerading as science. And with a few suggestive statements, they are scaring you. And misleading you. The CDC is flat-out lying to you. The foundation of the scientific process is not based on opinion. It’s grounded in science. And right now, the best science we have says, vaccines are less likely to cause autism than living with dads who mow the lawn on Tuesdays, because, after all, studies “have not ruled out the possibility” of that relationship yet.
Dr. Niran Al-Agba is a pediatrician in Silverdale and a regular opinion columnist for the Kitsap Sun. Contact her at niranalagba@gmail.com.