A Republican senator and medical doctor is publicly criticizing the Trump administration's response to a growing measles outbreak that has infected thousands of Americans and claimed multiple lives.

Senator Bill Cassidy of Louisiana, chairman of the Senate Health, Education, Labor and Pensions Committee, says the administration is not doing enough to encourage Americans to get vaccinated against a disease that is largely preventable.

"I have seen people die from vaccine-preventable diseases. You get vaccinated, you don't die. You're not vaccinated, you do die," Cassidy said during a CNN interview.

More Than 4,000 Cases and Counting

According to the Centers for Disease Control and Prevention, the United States recorded 4,080 confirmed measles cases as of October 8, 2026, compared with 2,289 during all of 2025.

Approximately 95% of this year's cases involve people who were either unvaccinated or whose vaccination status was unknown.

Pennsylvania has been particularly hard hit, with more than 1,100 cases and six deaths reported by state and local authorities. Federal officials have recognized fewer deaths under different reporting criteria.

The resurgence is particularly alarming because measles was declared eliminated from the United States in 2000, meaning the disease was no longer spreading continuously within the country.

Cassidy Challenges RFK Jr.

Cassidy directed his criticism toward Health and Human Services Secretary Robert F. Kennedy Jr., whose history of promoting vaccine skepticism has generated controversy throughout his tenure.

Although Kennedy and federal health officials have recommended measles vaccination during the outbreak, Cassidy argues the administration needs to promote immunization far more aggressively.

"My concern as a physician is that everyone should be vaccinated for measles," Cassidy told CNN's Jake Tapper.

He also emphasized that refusing vaccination can endanger others, including people who cannot receive vaccines for medical reasons.

The criticism comes after President Trump himself raised questions about the safety of established childhood vaccination schedules, despite decades of scientific evidence supporting their effectiveness.

A Preventable Public Health Crisis

Two doses of the measles, mumps and rubella (MMR) vaccine are approximately 97% effective at preventing measles.

Nevertheless, declining vaccination rates have left more communities vulnerable to outbreaks of a disease that can cause pneumonia, brain inflammation, permanent disability, and death.

Cassidy's criticism highlights a growing disagreement within Republican ranks over the administration's approach to public health.

While the Trump administration continues to face questions about its vaccine messaging, thousands of Americans have already contracted a disease that widespread immunization once made exceedingly rare in the United States.

The troubling reality is that America has the medical tools to prevent most of these infections. The challenge is convincing people to use them.