WASHINGTON (AP) — Republican Sen. Bill Cassidy wanted an assurance from Robert F. Kennedy Jr. before he would vote to put him in charge of the nation’s $1.7 trillion health department.

Kennedy’s history of promoting conspiracy theories or misspeaking about vaccines alarmed Cassidy, he said during a confirmation hearing earlier this year.

So, the Louisiana senator asked: “Can I trust that that is now in the past?”

Kennedy didn’t give a direct answer that day. Now three months into the job, however, Kennedy’s habit of casting doubts on vaccines has returned in interviews on television shows, public speeches and social media posts.

Kennedy will make his first appearance as health secretary before Cassidy’s powerful Senate health committee on Wednesday, when he’s expected to face intense scrutiny about the thousands of job he’s eliminated at the Department of Health and Human Services, the steep cuts he’s made to vaccination campaigns and his response to a measles outbreak that’s sickened 1,000 people.

He will speak about the agency’s budget request for the year, which includes a $500 million boost for his “Make America Healthy Again” initiative to promote nutrition and healthier lifestyles. The proposed budget also makes deep cuts, including to infectious disease prevention, maternal health and preschool programs.

The secretary plans to “share his vision on how HHS’ transformation will improve health outcomes, eliminate redundancies to save the American taxpayer, and streamline operations to improve efficiency and service,” HHS said in a statement to The Associated Press.

Kennedy’s supporters, meanwhile, have viewed his first three months in the job as a successful delivery of “MAHA” agenda items: He’s pressured food companies to ditch artificial dyes, promised to study the cause of autism, vowed to reverse fluoride recommendations and earned buy-in from several Republican governors to ban soda from the food stamp program, for example.

But many eyes and ears will be on Kennedy’s dialogue with Cassidy, who extracted a number of guarantees from Kennedy about his approach to vaccines. Those included promises to keep the current childhood vaccination schedule, use the current vaccine monitoring system and not remove statements that say vaccines do not cause autism on the Centers for Disease Control and Prevention website.

“I will watch carefully for any effort to wrongfully sow public fear about vaccines between confusing references of coincidences and anecdote,” Cassidy said earlier this year, after voting in favor of Kennedy’s nomination.

Kennedy has since delivered a mixed message on vaccines that public health experts have said are hampering efforts to contain the measles outbreak. He’s offered endorsements of vaccinations but continued to raise questions about their efficacy or safety. He’s said the childhood vaccine schedule will be examined in a study of autism’s causes. He’s called the measles, mumps and rubella vaccine — a shot given to children to provide immunity from all three diseases — “leaky,” although it offers lifetime protection from the measles for most people. He’s also said they cause deaths, although none has been documented among healthy people.

At the agency, too, he’s made moves that support the anti-vaccine movement. He hired a man who has published research that suggests vaccines cause developmental delays to oversee a study on autism. And he’s terminated some research and public health funds dedicated to vaccines.

Kennedy, who has rejected the anti-vaccine label, has regularly said that he is “pro-safety” and wants more research on vaccines, although decades of real-world use and research have concluded they safely prevent deadly diseases in children.

“His longstanding advocacy has always focused on ensuring that vaccines, and other medical interventions, meet the highest standards of safety and are supported by gold-standard science,” HHS said in a statement. “As he did during confirmation, Secretary Kennedy is prepared to address questions surrounding this topic.”