Sen. Bill Cassidy (R-LA) called on President Donald Trump to provide evidence for recent claims questioning vaccine safety as the United States records its highest number of measles cases in more than 30 years. Speaking on "Face the Nation" on Sunday, Sept. 20, 2026, Cassidy, a physician and chairman of the Senate Health, Education, Labor and Pensions Committee, responded to the president's recent executive order and public comments suggesting the measles, mumps, and rubella (MMR) vaccine could be "lethal" unless administered in separate doses.
The U.S. has recorded nearly 3,300 confirmed measles cases this year, according to Centers for Disease Control and Prevention (CDC) data, an increase from 2,300 cases last year and 285 cases in 2024. While the Trump administration has officially encouraged parents to vaccinate their children, the president recently stated in the Oval Office that he would "demand" drug companies split vaccines into five doses over six-month intervals. The president claimed without evidence that this change would lead to a "massive reduction in autism" and argued it would reduce the size of the vaccine doses.
Cassidy questioned the basis of the president's claims, asking who was advising him and what data supported the characterization of the MMR vaccine as "lethal." He cited recent deaths in Pennsylvania, including an 18-year-old and a 40-year-old, to emphasize that measles is not a "victimless experience." A spokesperson for the Department of Health and Human Services (HHS) responded by stating that any suggestion the administration is discouraging vaccination is "fake news" and noted that Secretary Robert F. Kennedy Jr. has stated the MMR vaccine is the most effective way to prevent infection.
The Senate Health Committee, chaired by Cassidy, is scheduled to hold a hearing this week for Heidi Overton, the president's nominee to lead the FDA. Cassidy stated he needs to hear Overton address the president's claims about vaccine lethality before deciding on her nomination. Meanwhile, Cassidy indicated he would support Nicole Saphier for Surgeon General after she testified that the MMR vaccine is not lethal. While some have discussed the possibility of impeaching Secretary Kennedy, Cassidy stated such an effort currently lacks sufficient support to succeed.