Correcting this week’s misinformation: week of September 24, 2026

President Donald Trump says he wants vaccine makers to split each vaccine into five doses to help autism rates go down.

• Vaccines do not cause autism, and splitting doses has no proven benefit.
• Smaller doses would need testing to make sure they protect children.
• Research suggests autism-related brain changes can begin before birth.

President Donald Trump has proposed splitting each vaccine into five smaller doses to lower autism rates. But research shows that vaccines do not cause autism. A study of more than 650,000 children found that children who received the MMR vaccine were no more likely to develop autism than those who did not. A 2025 World Health Organization review reached the same conclusion.

Scientists carefully study how much vaccine to give, how many doses children need, and how long to wait between doses. They do dose-ranging studies to make sure they use the lowest dose of a vaccine that will still work. Making vaccines with a dose lower than the ones we give means giving children a vaccine that will not work and will not help their bodies create immunity against terrible diseases.

Research also points to autism having roots in brain development before birth. In one study of children’s brain tissue, scientists found differences in how brain cells were arranged in most of the autistic children studied. These layers of cells form during pregnancy. The findings suggest that the differences began while the babies were still in the womb.

This study does not explain every case of autism. But it adds evidence that brain changes linked to autism can begin before childhood vaccines are given. Large studies also show that vaccines do not cause autism. There is no evidence that splitting vaccine doses would prevent it.

As a speaker at an anti-vaccine conference, HHS Secretary RFK Jr. said that we should focus more on the vaccine-injured. He also said that the Hep B vaccine was only studied for a short amount of time, that vaccines are not studied enough, and that vaccines cause chronic health conditions.

• Hepatitis B vaccine studies lasted much longer than four or five days. Those short periods tracked short-term reactions.
• Vaccines go through several stages of testing and review before approval.
• A health problem reported after vaccination does not prove the vaccine caused it.

RFK Jr.’s claims about hepatitis B vaccine testing leave out key details. He points to sections of the vaccine package inserts that describe watching babies for reactions for four or five days. But those sections focus on short-term reactions, such as soreness or fever. They do not describe the full length of the studies. The same inserts also describe follow-up periods of nine to 18 months. Before approval, vaccines go through several stages of testing and a review of their safety and how well they work. You can learn more about the vaccine approval process here.

He also points to lists of reported health problems in the inserts as proof that vaccines cause those problems. But a report alone does not show the cause. A vaccine side effect is a health change caused by a vaccine. An “adverse event” is a health problem that happens after vaccination, whether or not the vaccine caused it. These events can be reported during studies or after a vaccine is approved.

The inserts explain that reports sent in after approval have limits. On their own, these reports cannot show how often a problem happens or whether the vaccine caused it. Researchers need more evidence to answer those questions.

Peter McCullough’s organization is saying that vaccines contain “54 mg of alpha-gal-bearing gelatin” which can cause meat allergies and other health issues.

• AGS is a serious allergy that can develop after a tick bite.
• There is no evidence that vaccines cause AGS. Cases mostly occur where lone star ticks live.
• People with AGS should ask their health care provider about vaccines that contain gelatin.

Alpha-gal syndrome (AGS) is an allergy that can develop after a tick bite. People with AGS react to a sugar called alpha-gal, which is found in most mammals. These reactions can be life-threatening.

Their study suggests that gelatin in some vaccines, including some MMR vaccines, might cause this allergy. But there is no evidence that vaccines cause AGS. Although researchers are still studying how tick bites trigger the allergy, gaps in our knowledge do not show that vaccines are a cause.

Vaccination patterns also do not match where AGS is most common. MMR vaccines are given across the country, while AGS cases are mostly found in areas where lone star ticks live. This pattern supports the link to tick bites.

Some vaccines contain gelatin made from mammals. If a child already has AGS, their health care provider can help decide whether these vaccines are safe for them. A possible allergic reaction in someone who already has AGS is different from a vaccine causing the condition.