Nicole Brown Chau is a deputy managing editor for CBSNews.com. She writes and edits national news, health stories, explainers and more.

Some of the newest members of the Centers for Disease Control and Prevention's vaccine recommendations committee have questioned established medical research on immunizations and the COVID-19 pandemic.

In a press release shared Monday, the CDC and Department of Health and Human Services said five new members were appointed to the Advisory Committee on Immunization Practices, or ACIP -- just days ahead of a scheduled meeting that is likely to discuss the fall season's COVID vaccines and more.

"These appointments reflect the commitment of Secretary Robert F. Kennedy, Jr. to transparency, evidence-based science, and diverse expertise in guiding the nation's immunization policies," the release stated. But a look at the records of those selected shows some have voiced skepticism about vaccines and questioned evidence of their effectiveness.

This isn't the first time Kennedy, known for raising doubts about vaccines, has appointed people aligned with his views since taking over as HHS secretary. In June, he named eight new advisers after firing all 17 of the committee's previous members. His appointments include several allies he has worked with closely over the years and some members with a history as vaccine critics.

Kennedy appointed the new members directly, breaking with the past practice of agency officials vetting potential experts before sending them to the secretary for approval.

Here's a look at the newest committee members:

Catherine M. Stein is an epidemiologist and professor at Case Western Reserve University in Cleveland, Ohio. She received her doctorate in epidemiology and biostatistics from the same university in 2004 and has a focus on tuberculosis, according to her faculty page on the school's website.

Stein has been openly critical of the U.S. response to COVID-19 and has downplayed the severity of the pandemic. According to Ohio Capital Journal, Stein told Ohio lawmakers that health officials were inflating COVID-19 death and hospitalization numbers. The journal also tied her to Health Freedom Ohio, which is affiliated with Children's Health Defense, an anti-vaccine nonprofit founded by Kennedy as well as Ohio Advocates for Medical Freedom, which the journal describes as an anti-vaccine advocacy group.

Dr. Evelyn Griffin is an obstetrician and gynecologist based in Louisiana, according to Baton Rouge General's website. According to local reports, she has spoken against adding COVID-19 vaccines to the school immunization schedule as well as testified about adverse reactions of vaccines.

Hillary Blackburn, a clinically trained pharmacist, is also the daughter-in-law of Sen. Marsha Blackburn, a Republican from Tennessee, according to Politico.

She is currently the director of medication access and affordability at online pharmacy company AscensionRx and hosts the podcast "Talk to Your Pharmacist," the HHS release added. Her views on vaccines are unclear.

Dr. Kirk Milhoan, a pediatric cardiologist based in Hawaii, is a senior fellow at Independent Medical Alliance, a group that showed support for Kennedy's nomination, and the founder of For Hearts and Souls, a Christian medical missions organization.

At a 2024 panel discussion on vaccine injuries convened by Rep. Marjorie Taylor Greene, a Georgia Republican and vocal COVID vaccine skeptic, Milhoan claimed COVID shots pose more harm than good.

According to local news reports, he was also investigated by the Hawaii Medical Board in 2022 for disseminating medical misinformation but charges were eventually dropped.

Dr. Raymond Pollak is a transplant surgeon and hospital whistleblower. In 1999 he reported the University of Illinois at Chicago's hospital was diagnosing patients as sicker than they were to boost the number of transplants performed there, according to court documents.

New CDC advisory panel members include more COVID vaccine critics