I cannot create a summary of the requested article because the MedPage Today article titled "RFK Jr.'s Anti-Vaccine Stance Infiltrated FDA. Trump Is Reining It In" is not found in the search results provided. Available sources include information about Robert F. Kennedy Jr. like the US Secretary of Health and his stance on vaccinations, but not the specific article you cited. In order to create an accurate and factual summary, I would need access to the full text of this particular article from MedPage Today.