RFK Jr. questions vaccine safety at anti-vaccine organization gathering

Health Secretary Robert F.

Kennedy Jr. on Thursday returned to the the anti-vaccine group he founded, using a keynote address to signal the Trump administration isn't done questioning the safety of routine shots and expanding carveouts to federal mandates.

Why it matters: Though Kennedy avoided some of his most politically incendiary rhetoric, the speech made clear that the Department of Health and Human Services is working hard behind the scenes to continue reshaping federal vaccine policy.

He again questioned the safety of routine childhood vaccines and asserted they play a role in the development of chronic illnesses — questions that ignore decades of science supporting the vaccines' safety.

Driving the news: Kennedy spoke for more than an hour Thursday afternoon at a Children's Health Defense meeting in Washington, D.C., highlighting the Trump administration's work on healthy food before turning to vaccines.

He listed what the federal government is doing to reverse, in vaccine critics' eyes, decades of negligence on the issue.

And Kennedy assured the audience that President Trump is fully committed to the cause.

"He's directed us to pursue answers to strengthen vaccine safety, to expand options for families who want them and to preserve individual choice without federal mandates," Kennedy said.

"Let me be clear: You have a strong and steadfast friend at the White House." Between the lines: Kennedy addressed those frustrated with the administration's pace, in a nod to Make America Healthy Again movement members who feel he hasn't done enough to crack down on vaccines.

"In government, a bunch of things have to happen before something else happens, or you get sued, and it's a very laborious system, and there's a lot of inertia built in," he said.

"If we were able to overcome it, we would have changed things on day one, but those would have been short lived and I would have been out of a job." He certainly didn't sound like someone who's ready to leave office after the midterm elections, as has been rumored.

The backing he appears to have from Trump himself reinforces that.

"I didn't come to Washington to protect institutions from uncomfortable questions," he said.

"I came to make those institutions answer those questions, and I intend to stay in this fight as long as I am able." Reality check: The vast majority of health experts and scientists say that the question of vaccine safety is settled, pointing to reams of evidence accumulated over many years.