Is Aaron Siri right about vaccine safety?

In an interview on the Joe Rogan show, lawyer Aaron Siri argues that vaccines may cause health problems like autism or chronic illness and that the government and medical experts hide or ignore this evidence.

The idea that vaccines cause autism has been studied for many years. Scientists keep finding the same answer: vaccines do not cause autism.

The first claim came from a paper written in 1998 by a doctor named Andrew Wakefield. Later, scientists discovered that the paper was dishonest and based on false information. The journal removed the paper. Since then, many large studies have looked at this question. Some studies followed hundreds of thousands of children.

One study in Denmark followed more than 650,000 children. These studies found no difference in autism rates between children who were vaccinated and children who were not.

Scientists have also learned that autism begins very early in development, often before a baby is born. Differences in the brain linked to autism start forming in the womb. Genetics also plays an important role. Because of this, vaccines given later in infancy cannot be the cause.

Some people think the number of vaccines children receive might overwhelm the immune system or cause autism. But today’s vaccines actually contain fewer antigens (the parts that help the body learn to fight germs) than vaccines used decades ago. Autism diagnoses have increased mostly because doctors are better at recognizing it, and the guidance for diagnosis has improved. If vaccines caused autism, autism rates should have gone down as vaccine ingredients decreased. That did not happen.

Some studies claim vaccinated children have more autism than unvaccinated children. But many of these studies have problems. For example, families who vaccinate their children may visit doctors more often. Because of this, doctors are more likely to notice and diagnose developmental conditions. Children who rarely see a doctor may have autism but never receive a diagnosis.

Another claim says that government agencies hid evidence linking vaccines to autism. These claims often point to a 2000 scientific meeting called Simpsonwood. But later investigations, including a U.S. Senate review, found no evidence that scientists hid information. The meeting was simply scientists discussing early data and checking for possible safety issues, which is a normal part of research.

Serious reactions to vaccines are very rare. Most side effects are mild, such as soreness or swelling where the shot was given. The risks from vaccines are much smaller than the risks from the diseases they prevent.