Health Secretary Robert F. Kennedy Jr. defended his recent statements about vaccines during a congressional hearing on May 14.

“I’m going to tell the truth about everything we know and we don’t know about vaccines,” Kennedy told Sen. Chris Murphy (D-Conn.) while testifying before the Senate Health Committee. “I am not going to just tell people that everything is safe and effective if I know there are issues. I need to respect people’s intelligence.”

Several lawmakers expressed concern about Kennedy’s recent comments, which include saying that the protection conferred by the measles, mumps, rubella (MMR) vaccine wanes over time.

“The result is to undermine faith in the vaccine,” Murphy said.

“It’s kind of like saying, ‘listen, I think you should swim in that lake, but you know, the lake is probably toxic, and there’s probably a ton of snakes and alligators in that lake, but I think you should swim in it.’ Nobody is going to swim that lake if that’s what you say. I want you to acknowledge that when you say you support the measles vaccine, and then you go out and repeatedly undermine the vaccine, with information that is contested by public health experts, that is not supporting the vaccine.”

Kennedy responded, “If I advise you to swim in a lake that I knew there to be alligators in, wouldn’t you want me to tell you there were alligators in it?”

He added: “The reason people have lost faith in this program is that they’ve been lied to by public officials for year after year after year.”

Several outbreaks of measles have appeared in the United States this year, including an outbreak in Texas that has spread to hundreds of people. Texas officials say most patients are unvaccinated or have unknown vaccination status.

“We’re always going to have measles, as the vaccine wanes very quickly,” Kennedy said recently at a town hall.

Kennedy testified to the Senate panel and the House of Representatives Appropriations Committee. It was the first time he appeared before Congress since being confirmed in February.

Rep. Mark Pocan (D-Wis.) asked Kennedy, who has said his children received the typical vaccines in their childhood, if he had a child today, would he get that child vaccinated with the MMR shot?

“Probably,” Kennedy said. “I would say my opinions about vaccines are irrelevant.

“I don’t think people should be taking medical advice from me. I think if I answer that question directly, that it will seem that I’m giving advice to other people, and I don’t want to be doing that,” Kennedy said, adding that health officials were going to try to outline the pros and cons, or the risks and benefits, of each vaccine.

Pocan tried to get Kennedy to answer the same question for the chickenpox and polio vaccines. The health secretary demurred.

Republicans largely steered clear of vaccines during the hearings. A number of them praised developments under Kennedy, including the banning of some artificial dyes and the focus on cutting costs at the health agency.

“You’ve done more to shine the light on things that average Americans can do to make themselves healthier than almost any secretary that I can recall,” Sen. Jon Husted (R-Ohio) said, “so thank you for that service.”