A federal vaccine advisory committee made up of members hand-picked by Health and Human Services secretary Robert F. Kennedy Jr. recommended in an 8-3 vote on Thursday that the combined measles, mumps, rubella, and varicella (MMRV) vaccine should not be given before age 4, citing long-known evidence that shows a slightly increased risk for febrile seizures in that age group.

Experts say that while frightening, febrile seizures—which are uncommon after vaccination—are usually short-lived and harmless, and removing the option for parents could cause a decline in immunization rates against measles, mumps, and rubella, some of the most dangerous childhood diseases.

Known as the Advisory Committee on Immunization Practices, or ACIP, the group provides recommendations to the US Centers for Disease Control and Prevention on vaccine usage. These recommendations are typically adopted by CDC and have an impact on state vaccine requirements for school, insurance coverage of vaccines, and pharmacy access—something at least one member of the panel seemed to be unaware of.

Thursday’s vote is part of a new shift in vaccine policy being spearheaded by Kennedy, a longtime anti-vaccine activist. In his short time as HHS secretary, Kennedy has implemented restrictions on who can receive Covid-19 vaccines and dismissed all 17 sitting members of ACIP, replacing them with 12 new members—some of whom were installed just this week. Several of the new advisers have a history of criticizing vaccines or denouncing public health measures taken during the Covid-19 pandemic. Kennedy said a “clean sweep” of ACIP was necessary to build back public confidence in vaccine science.

On Thursday, committee members were asked to evaluate whether to recommend against the combined MMRV vaccine before age 4, as well as whether to delay the first dose of the hepatitis B vaccine until the child is at least one month old.

Currently, parents have two options for vaccinating their children against measles, mumps, rubella, and varicella, also known as chickenpox. They can choose the combined shot, known as MMRV, or two separate shots—one for MMR and another for chickenpox. About 85 percent of children get separate shots.

In the US, the hepatitis B vaccine is given in the hospital shortly after birth, because the virus can be transmitted to children during delivery. A serious liver infection, hepatitis B can lead to cirrhosis and cancer. Each year in the US, an estimated 25,000 infants are born to women diagnosed with the hepatitis B virus. Without vaccination, up to 90 percent of them would develop chronic infections. The World Health Organization advises a universal birth dose of the hepatitis B vaccine.

The topics of discussion at Tuesday’s meeting were not based on new data or evidence, and in fact, two ACIP members, Joseph Hibbeln and Cody Meissner, as well as several representatives from professional medical organizations who were in attendance, questioned why these changes were up for consideration.

Robert Malone, one of the more controversial new ACIP members, offered an explanation: “It’s clear that a significant population of the United States has significant concerns about vaccine policy and about vaccine mandates.” Malone is a former mRNA researcher who rose to prominence during the Covid-19 pandemic by spreading falsehoods about the disease and the vaccines; he abstained from Thursday’s vote because he previously served as an expert witness in a lawsuit over the mumps vaccine.

Senator Bernie Sanders published an op-ed in The New York Times on August 30, 2025, urging Health and Human Services Secretary Robert F. Kennedy Jr. to step down, citing what he calls a “crisis of confidence” in America’s public health institutions.

Sanders’ critique comes in the wake of a string of controversial actions by Kennedy, including the abrupt dismissal of CDC Director Susan Monarez, the disbanding of the Advisory Committee on Immunization Practices (ACIP) and the halting of nearly $500 million in federal funding for mRNA vaccine development.

According to Sanders, these actions “undermine scientific integrity, disrupt vaccine development, and threaten Americans’ access to life-saving healthcare.” He highlights the resignation of top CDC officials in protest as a stark signal that Kennedy’s leadership is incompatible with the responsibilities of HHS.

The op-ed frames the resignation as both a moral and practical imperative, stressing that political ideology must not override science in safeguarding public health and ensuring pandemic preparedness. Sanders warns that dismantling vaccine advisory structures and defunding research could leave the U.S. vulnerable to future outbreaks.

He also calls on Congress to hold HHS accountable for the upheaval, noting that the Trump-era appointee’s actions “threaten the public’s trust in health institutions that Americans rely on for safety and scientific guidance.” Sanders’ intervention signals rare but urgent congressional scrutiny of executive health policy, highlighting deep divisions over vaccine strategy, public trust, and governance.

“People can take control over their own health. They can take responsibility. They can see what food is doing to their glucose levels, their heart rates, and a number of other metrics as they eat it,” he said, referencing his “Make America Healthy Again” agenda slogan. “We think that wearables are a key to the MAHA agenda.”

RFK Jr. has taken his MAHA agenda one step further, making a big prediction on the $80 billion wearable tech industry, which encompasses the $13 billion glucose-monitor market.  

“My vision is that every American is wearing a wearable within four years,” he said.  

RFK Jr., however, walked back his sentiment in a statement about wearables to Axios this week, stating, “They are not for everyone because of concerns like cost and personal privacy.” 

Since taking the helm of the HHS, the secretary has enacted sweeping staffing changes in the department and has championed false claims about vaccines. Still, mitigating chronic diseases in the U.S. through preventive measures is at the forefront of his mind. 

Health wearables, such as sleep rings and glucose monitors, have gained popularity alongside a growing interest in preventive health. They track people’s heart rates, blood-sugar levels, and other vital signs. With arduous wait times and an evolving health care landscape, consumers are opting in for more data on their health outside the four walls of a hospital. 

“We’ve always believed that there’s a transformation afoot in the way people address their health, meaning that they’re going to be in charge of it,” Tom Hale, CEO of Oura, which produces the Oura sleep tracker, told Fortune earlier this month. 

RFK Jr. also previewed a “major advertising campaign” launching next week around preventive health, which will undoubtedly include wearables. 

However, democratizing access to wearables and ensuring they protect people’s privacy were among the key questions posed to RFK Jr. at the testimonial. Experts have widely warned of data breaches, given that tech companies are not subject to the same privacy controls as health systems and insurers. Moreover, wearables only improve health outcomes if people actually make behavioral changes. 

In addressing concerns, the secretary shared, “We are exploring ways of making sure that those costs can be paid for.”