Sen. Susan Collins, center, talks Thursday with attendees during the Maine Sheriffs Association breakfast at Joseph’s by the Sea in Old Orchard Beach. York County Sheriff William King Jr. is to the right of Collins. (Daryn Slover/Staff Photographer)

OLD ORCHARD BEACH — Sen. Susan Collins on Thursday criticized the Trump administration’s firing of the new director of the U.S. Centers for Disease Control and Prevention following a reported clash with Health Secretary Robert F. Kennedy Jr. over vaccine policy.

Susan Monarez, an infectious disease researcher who was sworn in a month ago, was notified by White House personnel Wednesday that she was fired, according to a statement her lawyer shared on the social media site X. He called the firing “legally deficient” because it did not come from the president himself.

“I am extremely alarmed at the firing of the CDC director,” Collins told reporters outside a breakfast for Maine sheriffs. “I know her. I have met with her several times and talked with her on the phone, and I see no basis for her firing. It is highly significant that her removal led to the immediate resignation of four other top officials who have served at the CDC for decades in some cases.”

Four other leaders at the CDC also resigned this week citing the politicization of their jobs and issues with leadership.

Collins said she has talked with the chair of the Senate committee that would have jurisdiction on the issue about what actions could be taken.

“The director serves at the pleasure of the president, so he does have the right to fire her,” Collins said. “She’s been on the job only three weeks, and I am very concerned about and alarmed by this removal.”

Sen. Susan Collins speaks Thursday during the Maine Sheriffs Association breakfast at Joseph’s by the Sea in Old Orchard Beach. (Daryn Slover/Staff Photographer)

Collins voted in February to confirm Kennedy, who has a long history of criticizing vaccines and falsely linking them to autism, to lead the U.S. Department of Health and Human Services. But she has also taken issue with some of his actions, such as cuts to National Institutes of Health research grants.

On Thursday, Collins said it was a “bad mistake” for Kennedy to remove in June all 17 sitting members of the CDC’s Advisory Committee on Immunization Practices, an advisory committee that makes recommendations on the safety, efficacy, and clinical need of vaccines.

“It’s fine to have some changeover, that’s very normal,” she said. “But to remove all of the members, that’s very alarming.”

Former Maine CDC director Dr. Nirav Shah raised similar concerns about management of the U.S. CDC in an interview last month. He stepped down from the No. 2 spot at the federal agency in February and has returned to Maine to teach at Colby College and, perhaps, run for governor.

Collins was in Old Orchard Beach to speak at the Maine Sheriffs Association annual summer retreat, where she delivered a 30-minute speech focusing on the issues of scams against the elderly, the opioid crisis and illegal marijuana grow houses.

Her appearance came as candidates are starting to line up for the Democratic primary to challenge her in 2026. On Wednesday, Gov. Janet Mills, whom national Democratic leaders are trying to recruit, said she is “seriously considering” running and may decide by November.

Graham Platner, a military veteran and oyster farmer, announced Thursday that his campaign has raised $1 million since he announced his candidacy a little over a week ago. David Costello, of Brunswick, and Jordan Wood, of Bristol, are also running, and another Democrat is expected to enter the race next week.

“The Democrats are clearly going to have a crowded primary, and it’s up to them, not me, to sort out who their candidate will be,” Collins said when asked about the race Thursday.

Moira Myers, of Old Orchard Beach, protests Thursday in front of Joseph’s by the Sea, where U.S. Sen. Susan Collins spoke during the Maine Sheriffs Association breakfast in Old Orchard Beach. (Daryn Slover/Staff Photographer)

Collins, long seen as one of the Senate’s most moderate Republicans, is facing scrutiny from both parties ahead of the election, with Democrats calling on her to stand up more often to President Donald Trump while Republicans want her to be more loyal to him.

In Searsport on Tuesday, protesters disrupted a ribbon-cutting ceremony Collins attended with shouts about her lack of town hall meetings, support for Israel and her recent votes on U.S. Supreme Court nominees.

A handful of protesters also gathered outside Thursday’s breakfast in Old Orchard Beach. Moira Myers carried a sign that said, “Prison without due process is a concentration camp,” which she said referred to “the immigration mess we’re in and people being taken off the street without cause.”

“She needs to stand up and follow her conscience, and the Constitution,” Myers said. “Use her voice and her power to stop all this.”