In September, the federal committee that makes vaccine recommendations voted to change the childhood immunization schedule. That in itself isn’t unusual; past committees have done so over the years. But this time, careful deliberations and evidence-based decisions, hallmarks of past meetings, were absent.
The committee removed the option for a combination vaccine as the first dose to protect against measles, mumps, rubella and varicella, better known as chicken pox. Now, 12- to 15-month-olds would get the chicken pox shot separately. The reason for the vote: a rare chance a child might have a febrile seizure, a usually harmless side effect that was already known.
The change may seem insignificant,sence the majority of parents already chose to separate the chicken pox shot for their kids’ first dose. But, along with comments by President Donald Trump and his top public health leaders raising doubts about other vaccines, it signals bigger changes to come, ones that could threaten the very foundation of the national childhood vaccination schedule.
Begun in the mid-1960s, this schedule has been a tremendous public health success. Today it protects people against close to 20 diseases, including polio, tetanus, hepatitis B and measles. It also helps prevent cancers of the cervix and liver.
But Trump named Robert F.Kennedy Jr., an anti-vaccine advocate, to head the U.S. Department of Health and Human Services. Kennedy then fired vaccine and public health experts on the Advisory Committee on Immunization Practices, or ACIP, the group that establishes vaccine recommendations. His replacements included people with similar antivaccine views and little expertise in vaccines.
The September meeting was a stark reminder that the new ACIP would not be following in the footsteps of its predecessors. Past ACIP committees have historically been known for their scientific rigor. For instance, when measles outbreaks occurred in 1989, the group recommended adding a second dose of the measles, mumps and rubella, or MMR, shot. Research later revealed a small but increased risk of febrile seizures with the combination with varicella, or MMRV, shot as a first dose.
A febrile seizure is a convulsion caused by a high fever due to viral illness or following certain vaccinations, or because of a genetic predisposition. Between 200 and 500 kids per 10,000 will have a febrile seizure for any reason, most often from the ages of 6 to 60 months. About 4 of every 10,000 kids who, for a first dose, get the MMR and chicken pox shots separately have a febrile seizure; about 8 in 10,000 do with the MMRV jab. While scary, they rarely cause harm. Still, ACIP in 2009 recommended that children get two separate shots for that dose,unless parents prefer the MMRV and have been told of the risk.
The new ACIP’s september meeting “was a clear departure from standard operating procedures,” said Helen Chu, an infectious diseases doctor at the University of washington School of Medicine in Seattle and a former voting member on ACIP, at a news briefing days later. Along with removing MMRV as an option for the first dose, the members discussed delaying the birth dose of the hepatitis B vaccine — despite a dearth of new evidence that would call for a review.
Then, Trump and HHS officials spent the next days sowing more doubt, questioning the safety of the MMR vaccine itself, in use for more than 50 years.They suggested it should be separated into three shots, even though the single vaccines are no longer available in the United States.
Combination vaccines are a staple of the childhood vaccination schedule, and for good reason. Children who get the combo shots are more likely to get all the doses for a vaccine and get them on time. They need fewer pokes and fewer trips to the doctor’s office to acquire full protection against diseases.
The premise that vaccines shouldn’t be combined “is a misunderstanding of how the immune system works,” says Flor Muñoz, a pediatric infectious diseases specialist and vaccine trials investigator at Baylor College of Medicine in Houston. A large body of evidence has refuted claims that getting multiple vaccines during early childhood weakens the immune system.
False information about vaccines has existed for about provided that vaccines have. In recent years, it’s been amplified by social media. At the state level, antivaccine legislation has been ramping up, with Florida even announcing plans in 2025 to abolish school vaccine mandates.
Now, questions about the safety and effectiveness of vaccines are coming from the federal government, too. The difference is, it has the power to make national policy, setting in motion changes that increase our vulnerability to preventable infectious diseases.
There is much to lose. A study from the U.S. Centers for Disease Control and Prevention estimates that among people born during 1994 through 2023, immunizations given during childhood will have stopped around 508 million cases of illness and will have prevented more than 1 million children’s deaths. If the Trump governance continues to chip away at the childhood vaccine schedule, the United States could, over time, return to the days when infectious diseases regularly hospitalized children and unnecessarily cut short young lives.
“It means that we will have a high chance of recurring outbreaks of some of the diseases that we’ve been able to control,” says pediatric infectious diseases physician and epidemiologist Andrew Pavia of the University of Utah in Salt Lake City. “Most people have never seen a child go deaf from measles,” Pavia says. “They’ve not seen a child develop terrible complications of regular flu and end up in the ICU.”
That is in part because of the decades of work by the many experts in public health, pediatrics, immunology and other scientific fields who have served on ACIP, culminating in a unified, national childhood vaccination schedule.Shots cover one or multiple pathogens and are given in different numbers of doses and at different times, starting at birth and continuing through the teenage years.
ACIP recommendations establish which vaccines must be covered by insurance and by the federal Vaccines for Children, or VFC, program. Created to address disparities in vaccine coverage, VFC provides vaccines at no cost to children and teens eligible for Medicaid, those who are uninsured or underinsured and American indian and Alaska Native youth. The program covers about half of U.S. kids.
Health insurance companies have announced they will continue to cover vaccines recommended prior to September 2025 until the end of 2026. But VFC must follow current ACIP recommendations. That means that with their September vote on MMRV, the new ACIP has taken a vaccine choice away from tens of millions of children. If the September meeting is a preview of more vaccine shifts to come, the country is headed toward a divide in vaccine access, putting the health of VFC kids at risk.
And eventually, it will affect everyone. Disparities can lead to pockets of unvaccinated and under-vaccinated children. Those pockets spur outbreaks. Take highly contagious measles. The first outbreak in 2025 began in Gaines County, Texas, where the MMR vaccination rate among kindergartners was only 82 percent, far below the 95 percent coverage needed to stop measles from spreading in the community.
Public health alarm bells are also going off regarding the committee’s discussion about the hepatitis B vaccine birth dose. If it is delayed or no longer given to all babies, past experience indicates dire consequences. Infancy is the most harmful time to become infected with the disease: Around 90 percent of infected infants will develop chronic hepatitis B. Chronic disease damages the liver and increases the risk of liver cancer. A quarter of people who become ill with hepatitis B in childhood will die prematurely.
As universal hepatitis B vaccination for infants was recommended in 1991, the total number of reported hepatitis B cases has fallen from around 18,000 a year to about 2,200 in 2023. And cases among children and teens have almost completely vanished. A universal approach for newborns “has been a tremendous success that’s benefited many, many children,” Pavia says. Without it,“almost certainly,more children will end up getting infected with hepatitis B.”
To counter federal leaders’ attacks on vaccines, medical societies and some states are stepping in. The American Academy of Pediatrics, the Infectious Diseases Society of America and others have been providing trustworthy vaccine information and countering falsehoods. Parents can look to AAP’s childhood vaccination schedule for the most recent, evidence-based version. Some states have formed public health coalitions to provide vaccine recommendations, although a patchwork approach can’t do what a unified vaccine schedule can. “Diseases don’t respect state borders,” Chu said.
So far, there is still widespread support for childhood vaccines among parents, with around 9 in 10 saying it is indeed critically important for kids to get MMR and polio shots, according to a KFF-Washington Post poll released in October. About 8 in 10 want public schools to require these vaccines. Pavia hopes this confidence in vaccines “will counteract this hijacking of health care.”
Because of the success of childhood vaccinations,we can focus on other health issues children face,Muñoz says. “The growth and ability of children to thrive in all aspects of their lives has been supported in great part through prevention of infectious diseases.”
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