Health Secretary Robert F. Kennedy Jr. advised parents of newborns to “do your own research” before vaccinating their infants during a televised interview in which he also suggested the measles shot was unsafe and repeatedly made false statements that cast doubt on the benefits of vaccination and the independence of the Food and Drug Administration.

Mr. Kennedy made the remarks to the talk show host Dr. Phil in an interview that aired Monday on MeritTV to mark the 100th day of the Trump administration. He said, as he has in the past, that “if you want to avoid spreading measles, the best thing you can do is take that vaccine.”

But Mr. Kennedy also made clear, as he has in the past, that he believes it is up to individuals to decide. In suggesting vaccines are unsafe, he contradicted decades of advice from public health experts, including leaders of the Centers for Disease Control and Prevention.

“I would say that we live in a democracy, and part of the responsibility of being a parent is to do your own research,” the health secretary said, in response to a question from a woman in the audience who asked how he would advise a new parent about vaccine safety. “You research the baby stroller, you research the foods that they’re getting, and you need to research the medicines that they’re taking as well.”

The phrase “I did my own research” became a cultural and political touchstone during the coronavirus pandemic, when proponents of vaccination, mostly on the political left, used it to denigrate those who had chosen not to get vaccinated. It became an internet meme and popped up on mock tombstones in Halloween-themed graveyards in liberal neighborhoods.

The Department of Health and Human Services did not immediately respond to a request for comment.

Mr. Kennedy’s comments came amid the largest measles outbreak in about 25 years in the United States, which has included the deaths of two young children and an adult.

Dr. Paul Offit, a pediatrician and vaccine expert at Children’s Hospital of Philadelphia who has often been at odds with Mr. Kennedy, said that it was “perfectly reasonable to be skeptical of vaccines,” but that parents who wanted to do their own research must be careful about their sources of information.

“What doing your own research should mean is that you should talk to, or at least look at online, people who have an expertise in the field, which doesn’t mean looking in chat rooms or just on social media blog posts,” Dr. Offit said. He added that while there is good information available, “there’s also a lot of really bad sources of information that will miseducate you about your choice. And Robert F. Kennedy Jr. is a perfect example of that.”

Another vaccine expert, Dr. Peter Hotez of Baylor College of Medicine in Houston, said Mr. Kennedy was being disingenuous. “He says that — doing your own research — knowing full well that when a parent does their own research, they are now mostly downloading an onslaught of disinformation — a lot of it from the health and wellness, nutritional supplement influencer industry trying to peddle alternatives.”

Mr. Kennedy also suggested, without evidence, that measles shots cause a variety of ailments. “Does it stop measles?” he asked. “Yeah, but does it also do something else, cause you seizures or cause neurological or autoimmune disease? We don’t know. Nobody can answer that question.”

In fact, studies have shown that, with rare exceptions, people who are vaccinated are less likely than those who suffer infections to develop autoimmune diseases, which has led researchers to conclude that vaccines “have not only the potential to protect the patient from infectious diseases, but also from its complications, including autoimmune manifestations.”

Mr. Kennedy’s other statements in the interview were also rife with inaccuracies. “New drugs are approved by outside panels, not by the F.D.A. or the C.D.C.,” he declared.

That is false. Outside panels of experts do advise the F.D.A. on controversial or high-profile drug approval decisions, and some panel members have ties to industry that are publicly disclosed before the meetings begin. But the F.D.A. alone has authority to approve or reject new drugs, vaccines and other therapies. The C.D.C. has no role in drug approvals whatsoever.

“Mr. Kennedy needs a briefing on drug development and F.D.A. decisions about marketing,” said Dr. Robert Califf, the agency’s commissioner under President Joseph R. Biden Jr. “He is either ignorant on the topic or intentionally misleading the public. Outside panels are advisory. F.D.A. makes the decisions.”

Mr. Kennedy also insisted, inaccurately, that vaccines are not evaluated for safety either before or after they are licensed. “There’s no safety studies at the outset, there’s no surveillance system afterward,” he said, adding, “Vaccines are the only medicine or medical product that is exempt from pre-licensing safety testing.”

In fact, the Food and Drug Administration licenses vaccines after a yearslong process that begins with extensive testing in the lab and in animals and progresses to trials in humans. The F.D.A. requires careful studies of vaccine safety and effectiveness, often with thousands of people in large trials, said Dr. Peter Marks, the agency’s vaccine division chief who was recently forced to resign from his position.

“I don’t know where this misunderstanding is coming from,” said Dr. Marks, who has been critical of Mr. Kennedy. “Vaccines are required to be extensively studied for safety. By definition, we’re giving these products to healthy people. So safety is paramount.”

After vaccines are licensed, they are monitored via an alphabet soup of databases. The Vaccine Safety Data Link system has relied on electronic health records from medical centers across the country. It has been responsible for detecting unusual side effects, including rare cases of myocarditis, or inflammation of the heart muscle, among young men who took Covid-19 vaccines.

Another system, the Vaccine Adverse Event Reporting System, developed in 1990 as a “national early warning system,” relies on reports from patients and providers. Although many vaccine critics, including Mr. Kennedy, have cited VAERS data to argue that vaccines are dangerous, the system was not designed to determine if vaccines cause health problems. It was designed to pick up hints that can be investigated further in other types of data systems.

The F.D.A. has an additional safety monitoring program called BEST, or the Biologics Effectiveness and Safety Initiative.

Dr. Sean O’Leary, the chairman of the committee on infectious diseases for the American Academy of Pediatrics, said it was wrong to claim that federal officials did not keep an eye on vaccine safety. “I don’t know where this is coming from,” he said, “because none of it is true.”

He added: “We are aware of many rare adverse events. If it becomes clear that the risks are even close to outweighing the benefits, the vaccine gets pulled from the market.”