Dr. Mehmet Oz, head of the Centers for Medicare and Medicaid Services, on Sunday countered President Donald Trump's recent claims that the measles, mumps and rubella — or MMR — vaccine could be lethal.

In an interview with CBS' "Face the Nation," host Margaret Brennan repeatedly asked Oz to clarify the president's remarks before he finally stated, "The MMR vaccine is not a lethal vaccine."

Earlier this month, Trump signed an executive order to overhaul the government's vaccine recommendations, including splitting the MMR vaccine into multiple shots, despite concerns around measles outbreaks around the nation.

The Merck MMR vaccine has been in use for more than 40 years. Since 2021, more than 800 million doses of the vaccine have been administered across more than 75 countries. But during the signing, Trump asserted that there is a "possibility they are quite lethal" together. The president provided no evidence to substantiate that claim.

"Separately, they are not at all lethal but very effective," Trump added. While two versions of the combined vaccine are available in the U.S., individual shots for each disease are not.

"The president twice said that the shot may be lethal," Brennan said Sunday. "Do you want to clarify that?"

Oz initially responded, "We want the patients to make the —"

But Brennan cut him off, once again asking Oz to clarify the president's remarks.

"The president wants Americans — he said this many times — to get to the doctors as often as they can," Oz said. "And it's hard for parents to answer the questions."

"MMR is not offered in three shots," Brennan said. "Merck could not offer that. The president called that single shot lethal. Do you want to clarify that?"

"The MMR vaccine is not a lethal vaccine," Oz answered.

It is the second time this month Brennan has become entangled with some of the administration's health care officials following a tense interview with Jay Bhattacharya, the National Institutes of Health director. Also this month, CNN's Dana Bash had a strained interview with Health and Human Services Secretary Robert F. Kennedy Jr. on some of the same issues.