The United States CDC has abandoned science in its new advice about vaccines and autism

The United States Centers for Disease Control and Prevention (CDC) has revised its longstanding guidance about vaccines and autism.

- HASSAN VALLY

The guidance once stated clearly and correctly that the evidence shows no link between vaccines and the development of autism.

Now it claims “studies supporting a link [between vaccines and autism] have been ignored by health authorities”. It also says:

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.

Health Secretary Robert F. Kennedy Jr directed the CDC to make these changes, despite promising at his confirmation not to alter the CDC’s vaccine advice.

With this change in wording on the website the CDC has been dragged to a new low. The CDC once stood as a global benchmark of scientific integrity. Sadly, it now risks becoming a megaphone for misinformation and a tool for those whose goal is to undermine science.

Let’s look at the updated CDC statement about vaccines and autism, and how this is at odds with how science works.

Saying “studies have not ruled out the possibility that infant vaccines cause autism” is in direct conflict with how science works.

Using science, we can demonstrate that two things are linked by showing consistent, reproducible associations that stand up across multiple study designs. We can also test a hypothesis repeatedly and from many angles.

Therefore, for example, when high-quality studies using different methods, populations and measurements, all fail to find a link between vaccines and autism, the rational conclusion is there is no causal connection.

But we cannot prove the universal absence of a link.