President Donald Trump said in an oval office address on September 18, 2026 that childhood vaccines should be given in smaller doses and should be separated over longer periods of time.

He stated , “instead of a child going in and having a tremendous amount of different vaccines pumped into a big proportion of the body…we’re going to recommend that they do five doses marked one, two, three, four, five and that they be given in six month intervals, so that a small amount of vaccine gets pumped into the body”.

This claim raises two separate questions: can multiple vaccines overwhelm a child’s immune system and should vaccines be given further apart in time?

Here is what the science and leading medical societies say.

Do Vaccines Overload The Immune System?

The current scientific evidence does not support the idea that routine childhood vaccination overwhelms a healthy child’s immune system.

A 2018 JAMA study by Glanz and colleagues examined 944 children and compared those who developed infections not targeted by vaccines with children who did not. Children who developed these types of infections had received an average of 240.6 vaccine antigens (the proteins that stimulate an immune response in the body) during their first 23 months of life, compared with 242.9 among controls. The authors concluded this was not statistically significant. Since the number of vaccine antigens was essentially identical in the two groups, this provides evidence that vaccines did not contribute to weakening the immune system or making children susceptible to infections not targeted by the vaccines. Thus, the number of antigens in vaccines did not overwhelm the immune system.

In addition, children that receive vaccines in the United States are exposed to much fewer antigens compared to 30 years ago, despite protection against more diseases. In the 1980’s, children were exposed to more than 3,000 antigens , compared to fewer than 200 today.

Should Vaccines Be Spaced Further Apart?

The President also suggested vaccines should be spaced out at six month intervals as a safety precaution. Trump has also previously suggested breaking up the MMR vaccine, a single shot into three separate shots. However, decades of research shows the MMR vaccine to be safe and effective administered as it is currently, as a single shot when the child is between 12 months and 15 months of age, and again when the child is between 4 and 6 years of age.

The American Academy of Pediatrics also notes that vaccine doses and timing are determined through extensive testing and studies that have found simultaneous administration of multiple vaccines to be safe. In addition, delaying vaccination and separating doses may provide unnecessary barriers for some children from actually getting vaccines, leading kids to become vulnerable to various infectious diseases.

The President, in his address , also suggested that the federal vaccination changes he was describing would lead to a “massive reduction in autism”. However, decades of research has unequivocally shown no causal link between vaccines and autism. A 2025 Danish study involving more than 1 million children found no link between vaccines and autism.

In addition, the World Health Organization published a 2026 systematic review examining studies from 2010 to 2025, and concluded that the strongest and most rigorous studies did not support a causal relationship between vaccines and autism. Studies reporting positive associations were judged to have low-strength evidence and a high risk of bias.

Trump’s proposal to reduce or separate vaccine exposure is a policy proposal that could be studied. However, there is a significant amount of research that has already studied the President’s proposal, and his claims made are not currently supported by the current body of scientific evidence.