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The Centers for Disease Control and Prevention's Advisory Committee on Immunization Practices is and Friday of this week under an unaccustomed spotlight. The committee, known as ACIP, usually attracts little attention as it deliberates schedules and eligibility, but suddenly finds itself navigating political scrutiny, public skepticism and internal upheaval.

The stakes extend well beyond the technical details of dosing intervals or eligibility cutoffs. The panel's decisions could reshape public trust in childhood vaccines, restrict access to vaccines through Medicaid and Medicare, and signal whether scientific consensus or political pressure will steer the nation's vaccination strategy.

The precise language of the measures the ACIP will be voting on has not been shared with CDC staff or made public, but here is what CDC experts believe may be on the table:

At a hearing on Wednesday of the Senate Committee on Health, Education, Labor and Pensions, and former CDC Chief Medical Officer and Deputy Director for Program and Science Dr. Debra Houry of a CDC under political siege.

In her remarks, Monarez recounted , saying it came after she refused to pre-approve new vaccine policies and insisted that to be credible, such decisions cannot be divorced from scientific evidence. 

Houry, who hours after Monarez was ousted, said, "Secretary [Robert F.] Kennedy [Jr.]'s actions repeatedly censored CDC science, politicized our processes, and stripped agency leaders of the ability to protect the health of the American people." She added, "I could not in good conscience remain under those conditions."

Together, their accounts paint a picture of personal views and political positions increasingly overriding science, thereby eroding the CDC's core mission. The fallout, critics say, is likely to be measured not in headlines, but in children's lives.

The administration is pushing back on this narrative. Andrew Nixon, an HHS spokesperson, charged that Monarez "was tasked with returning the CDC to its core mission after decades of bureaucratic inertia, politicized science and mission creep corroded its purpose and squandered public trust. Instead, she acted maliciously to undermine the president's agenda and was fired as a result."

Inside the agency, , the acting CDC director and deputy secretary of HHS, struck a different tone in an email to CDC staff obtained by Autos News. He highlighted the CDC's history of victories — from malaria eradication to identifying HIV — and argued that over time the agency had drifted from its core mission. "Not every health decision is the government's business. … CDC and other science agencies lost the American public's trust and faith during the later stages of the COVID-19 pandemic, but we are working hard to refocus and earn that trust back," he wrote. "Rigorous science, transparency about data and reasoning, and treating our fellow citizens as adults who can make their own informed decisions will be well received whenever we can offer them."

The competing narratives have left CDC staff caught in the middle. One longtime CDC staffer put it bluntly: "Part of this upcoming [ACIP] meeting is really all about criticizing the data." The staffer said the imperative inside the agency has shifted from one of problem-solving to point-scoring: "It feels less about protecting the public and more about putting science on trial," as the staffer put it.

What makes this week's ACIP meeting striking is not only the agenda — votes on the combined measles-mumps-rubella-varicella (MMRV) vaccine, the universal newborn hepatitis B vaccine dose, and COVID vaccine eligibility — but who will be voting. 

In June, Kennedy of ACIP and replaced them , many of whom have questioned vaccine safety or mandates. Then, just days before this week's meeting, he appointed , bringing the total of his picks now serving on the panel to 12.

Some of the new members include controversial figures: Dr. Robert Malone, who has spread misinformation about COVID vaccines; biostatistician Martin Kulldorff, who opposed vaccination mandates for children; and Catherine Stein, who has downplayed the severity of COVID. Dr. Kirk Milhoan, a pediatric cardiologist, has promoted ivermectin and hydroxychloroquine despite studies showing they are not effective treatments for COVID, and warned against vaccinating children despite evidence of benefits. Others, like pharmacist Hillary Blackburn and surgeon Dr. Raymond Pollak, are not vaccine specialists by training.

Critics note that several appointees have served as paid expert witnesses against vaccine makers, posing potential financial, professional, and ideological conflicts of interest. Normally, vetting of ACIP members takes months or years, with careful conflict-of-interest checks. Kennedy's accelerated appointments, combined with Monarez's forced resignation, have triggered alarm among career scientists.

At its June meeting, the ACIP abandoned its long-standing and featured what numerous scientific, medical and public health experts regarded as inaccurate claims by new members, as well as a presentation from a well-known anti-vaccine advocate. This week, the concern many experts have is whether scientific rigor can prevail.

CDC staff members emphasize that the precise wording of the measures ACIP members will vote on has not been disclosed. What insiders expect, however, is a narrowing of the list of conditions that classify someone as being at high risk for severe COVID. That shift could mean fewer people would be recommended for vaccination even if they might still benefit.

, a prior ACIP working group lead who resigned from the CDC earlier this year, warned that limiting recommendations could send the wrong signal, saying, "People may interpret a narrower recommendation as meaning the vaccine doesn't work, when in fact it's still highly protective against severe disease."

The possible exclusion of healthy pregnant women and healthy infants from the high-risk category is also drawing attention. Pregnancy and early infancy have long been recognized as periods of elevated vulnerability, and experts worry that dropping these groups from the recommendation would not only reduce their protection but would erode public confidence in maternal and pediatric vaccination.

Last month, the (AAP) recommended that all infants and toddlers aged 6 to 23 months . The group cited data showing that children under 2 have the highest COVID hospitalization rates among pediatric age groups, comparable to adults aged 50-64, and that more than half of those hospitalized had no underlying conditions.

The , the national organization representing high-risk pregnancy experts, has reaffirmed its recommendation that all pregnant and breastfeeding women receive the COVID vaccine.

And the , which includes Washington, Oregon, California and Hawaii, has recommended that all adults and children who want a COVID vaccine in those states can get one. Those recommendations are informed by the AAP, American College of Obstetricians and Gynecologists, and the American Academy of Family Physicians.

, who oversaw data on COVID hospitalizations, noted that pregnant women and infants remain uniquely vulnerable, making the question of maternal and early childhood COVID vaccination particularly sensitive. Havers resigned from the CDC earlier this year, saying she no longer had confidence that the data collected by her team would be used objectively or evaluated with appropriate scientific rigor to inform vaccine policies.

Less clear is whether ACIP will also raise the age threshold for routine vaccination from 65+ to 75+. Dr. Helen Chu, an infectious disease physician at the University of Washington, emphasized that while severe outcomes are rarer in the 65-74 group, simultaneous issues such as diabetes and heart disease complicate the picture. "Age is a blunt instrument," she said.

Hepatitis B remains a global killer, causing from liver cancer and cirrhosis.

Dr. Samuel So, director of the Asian Liver Center at Stanford University, calls the universal newborn hepatitis B vaccine "one of the most successful public health initiatives of the past 30 years."

The U.S. shifted from targeted to universal infant vaccination in 1991  too many cases of hepatitis B among pregnant women were missed during prenatal care. In 2005, the ACIP recommended , and in 2018 tightened the timing to . 

The rationale was clear: Even with screening guidelines, about pregnant patients were not tested for hepatitis B. A universal birth dose serves as a safety net, protecting infants whose parent's infection has been missed while also boosting on-time series completion.

Before birth-dose policies took hold, the U.S. saw . When infection occurs at birth, develop chronic hepatitis B and from cirrhosis or liver cancer if they're not treated. The risk is set at birth.

Reconsidering the birth-dose alarms experts. "Undoing decades of progress," Dr. So warns, would leave many at risk for a preventable type of cancer. And Dr. Anna Lok, director of clinical hepatology at the University of Michigan, warns that "even when it [hepatitis B vaccination] is recommended and it should be done in every newborn baby, we know it's not always done. And when it becomes optional, it means that it will be rarely done. And that is going to be the problem."

Alex Lee, a 68-year-old retired civil engineer and volunteer with in San Francisco, said the stakes are painfully personal. Lee acquired hepatitis B from his mother. He later developed cirrhosis and then liver cancer before a life-saving transplant in 2013. His mother also required a transplant, and two of his siblings live with the virus. 

"I didn't want my daughters to go through what I went through," Lee said. "That's why I made sure they all got vaccinated. Pulling back now would be a huge mistake."

For parents, the MMRV vaccine offers an obvious convenience: one shot instead of two.

But the combination vaccine carries a slightly higher risk of fever-related "febrile" seizures when used as the first dose in young toddlers aged 12-23 months. That risk , not the fact that it is a first dose. Febrile seizures are most common between 14 and 18 months of age, when children are naturally at peak susceptibility. Febrile seizures are rare and almost always resolve without lasting effects, but are frightening for families and can erode trust in vaccines.

"That's why  splitting MMR and varicella [vaccines] at 12 to 23 months. There was no reason to change the second dose, where no excess risk has ever been seen," explained one CDC expert.

By contrast, studies show no elevated risk when MMRV is given for the second dose at ages 4 to 6 years old, after children have outgrown the highest-risk window. Reconsidering recommendations without new evidence has led experts to wonder why the issue is being reopened and whether it risks sowing doubt.

What happens at the ACIP meeting in Atlanta this week is unusual, not just for the agenda, but for what it represents. Reevaluating long-standing vaccine guidance is rare; experts fear that doing so in such a politicized and polarized climate is riskier still. 

A found that about one in three parents now say they should be able to decline routine school-entry vaccines for their children, even if that creates . That's up from 16% in 2019 and a sign of growing unease about routine childhood vaccination. A confusing or seemingly inconsistent decision from the CDC panel could deepen distrust at a fragile moment.

Even the process itself may prove consequential. If CDC scientists are marginalized, as insiders suggest, the ACIP risks becoming a stage for ideological performance rather than scientific review. One CDC staffer put it bluntly: "Part of this upcoming meeting is really all about criticizing the data." The staffer went on to say, "It feels less about protecting the public and more about putting science on trial."

According to , the national trade association representing the health insurance industry in the United States, commercial "[h]ealth plans will continue to cover all ACIP-recommended immunizations that were recommended as of September 1, 2025… through the end of 2026." This includes updated formulations of the COVID and influenza vaccines. But vaccine coverage under Medicare and Medicaid may change based on new ACIP recommendations.

However, the real test will be the public's reaction. Will most parents still accept that the MMRV vaccine remains safe? Do hospitals continue to administer the hepatitis B vaccine at birth? Do older adults, confused by shifting COVID guidance, skip shots altogether?

"Process matters because trust matters," Houry said in her prepared testimony. "If people believe outcomes are predetermined, or that recommendations are slanted by ideology rather than scientific data, they are less likely to accept even well-supported recommendations," she said.

This week's ACIP meeting will test whether that trust can endure, not only in the science of vaccines but in the institutions charged with safeguarding them.