Powerful federal advisers this week are expected to make a controversial change to how babies are immunized against hepatitis B, and to question how pediatricians inoculate children against more than a dozen other infectious diseases, including measles, mumps, whooping cough and polio.

The Centers for Disease Control and Prevention’s Advisory Committee on Immunization Practices (ACIP) is convening Thursday and Friday for a closely watched meeting to rethink fundamental elements of the childhood vaccination schedule, which has protected children from dangerous diseases for decades.

The potential changes are welcomed by allies of Health and Human Services Secretary Robert F. Kennedy Jr., who has long questioned the safety and effectiveness of vaccines.

“We’re now starting to see truth telling about vaccines, and needless to say, pharma, medicine, academia, mainstream media are not happy,” Mary Holland of Children’s Health Defense said in a video posted to the group’s social media page. The nonprofit advocates against vaccines and was co-founded by Kennedy.

The meeting underscores grave concerns among many public health experts, who fear it will further erode childhood vaccinations, leading to a resurgence of preventable infectious diseases.

“We now seem to have entered a dangerous new phase in Secretary Kennedy’s campaign to shut down scientific expertise, silence the best available evidence, and replace it with his own personal agenda,” said Dr. Sean O’Leary, a professor of pediatric infectious diseases at the University of Colorado Anschutz who chairs the American Academy of Pediatrics’s committee on infectious diseases.

The CDC’s advisory committee, established in 1964, had long been considered a definitive source of information about childhood vaccines. It wields enormous power because its recommendations influence how doctors vaccinate patients and dictate whether insurance companies pay for shots.

But the committee has lost the trust of most mainstream medical groups since Kennedy replaced its members in June with his own slate. The committee has also abandoned longstanding collaborations with medical groups like the pediatrics academy and draws less on the experience of CDC experts.

The committee’s September meeting devolved into chaos. A scheduled vote on the hepatitis B vaccine was tabled amid confusion. The chairman was replaced this week. The new chair, Dr. Kirk Milhoan, is a pediatric cardiologist and fellow with the Independent Medical Alliance – a group which continues to recommend treating COVID with drugs like ivermectin, even though studies have shown it does not work.

Confidence in the CDC was further eroded last month when the agency changed its stance on whether vaccines may cause autism, a theory championed by Kennedy and other anti-vaccine activists but long debunked by a large body of high-quality research.

In response, many independent medical groups, such as the American Academy of Pediatrics, the American Academy of Family Physicians and a newly formed effort at the University of Minnesota called the Vaccine Integrity Project, have begun issuing independent recommendations, which some states have begun following instead.

Vaccine schedule under the microscope

The vaccine committee is expected to hear the first report by a new working group tasked with scrutinizing the childhood vaccine schedule. The schedule is the finely calibrated timetable pediatricians use to administer the sequence of more than 30 doses to protect against more than a dozen diseases.

The scrutiny is especially troubling to many public health authorities, coming amid new outbreaks of vaccine preventable diseases, which are on the rise because of falling immunization rates.

“We have seen more measles cases in our country this year than we have in recent history. In my own community, we’re seeing quite significant upticks in pertussis,” said Dr. Raynard Washington, director of the Mecklenburg County Public Health Department, based in Charlotte, N.C., “Any barriers [to vaccination] that might be created by bureaucracy or process pose a threat to the public’s health.”

Vaccine proponents say every vaccine is carefully evaluated for safety and effectiveness before being added to the schedule. And researchers and regulators monitor all vaccines for safety issues after doctors start using them.

Children receive the roster of shots at a young age to make sure they don’t catch dangerous diseases when they’re most vulnerable, experts say.

“Every vaccine on that schedule and the recommended timing of it exists for a reason,” says pediatrician O’Leary. “It’s based on the age at which a child’s immune system can provide optimal protection after vaccination, balanced with the age when the child is at highest risk for a disease. There’s no reason to delay or space out vaccines – doing so just puts children at risk.”

Some who are worried about vaccines argue the number of different antigens and other ingredients could overwhelm a child’s immune system. But supporters say children are exposed to far more immune stimulation from naturally occurring microbes than from vaccines. And vaccines have been refined over the decades to minimize the number of ingredients they contain.

“Imagine saying we can only use medicines now that were developed before 1990,” O’Leary says. “Imagine where we would be in medicine today. These newer vaccines are a good thing. They save lives. That’s why we give them.”

A change for the hepatitis B vaccine 

The first concrete step expected from the committee is a vote to change the current recommendation that all babies get vaccinated against hepatitis B within the first 24 hours of life.

It’s unclear what the committee might recommend, but it could include delaying the shot or requiring a detailed discussion with parents before administering the shot.

Proponents of the change argue universal vaccination at birth is unnecessary because hepatitis B is often spread through sexual contact and drug use. Babies could be protected by increased screening of pregnant women and only inoculating babies of mothers who test positive, some argue. Supporters of the change also point to other countries that don’t give newborns the dose.

But hepatitis B spreads other ways. The virus is highly infectious, and can be transmitted through contact with an infected person’s body fluids, such as their blood. People can also get infected by coming into contact with common household objects, such as toothbrushes, and towels, that have been contaminated by another family member.

A new analysis by researchers who have presented at past ACIP meetings finds that delaying hepatitis B vaccination by just a few months could lead to more than $222 million in excess healthcare costs and hundreds of preventable deaths each year.

Most babies infected with the virus end up with chronic infections, which increases their risk for liver disease, failure and cancer.

“Universal vaccination has been the cornerstone of hepatitis B elimination efforts for decades,” says Eric Hall, assistant professor of epidemiology at Oregon Health and Science University, and a co-author on the analysis. “It’s very important we continue this work and do not undo the important public health achievements of the past 45 years.”

Inoculating all babies at birth has resulted in a dramatic decrease in hepatitis B infections.

“The hepatitis B vaccine has one of the most well-established safety records of any vaccine, and it’s one of our best,” O’Leary says. “We’ve been using it for a long time. It’s one of our best tools to protect babies from chronic illness and liver cancer. This is a situation where one missed case is too many.”

He added that pediatricians partner with parents on children’s health. “You probably will also hear a lot from individuals in this meeting who claim parents don’t get a say in their children’s immunizations,” he said. “I want to be very clear when I say that’s completely false. … We want to make sure we’re protecting children from harmful diseases while also making sure the parents are fully informed and involved in the process.”

In addition, proponents of universal hepatitis B vaccination at birth argue there is no evidence the current approach is unsafe. And delaying the first dose would cause major problems because the subsequent two doses are administered as part of combination vaccines.

Experts are also alarmed that the CDC is investigating splitting up the MMR vaccine, which protects kids against measles, mumps and rubella in one shot. Giving kids three separate shots would mean more trips to the doctor and more needles, vaccine proponents say. They worry that, inevitably, more kids would end up missing vaccines.

Aluminum ingredients under fire

The committee is also studying the safety of an ingredient commonly used in vaccines, an additive that contains aluminum. Coming after other recent changes to vaccine policy, many public health experts worry that the administration may now try to remove the ingredient.

For almost a century, some important vaccines, including shots that protect against diphtheria, tetanus, hepatitis and the flu, have included aluminum salts, compounds that contain small amounts of aluminum. They are used as adjuvants to give the immune system an extra boost to make the shots protective.

“What aluminum does is it draws the immune system’s attention to that particular little protein so that it makes a much more robust immune response that you then are protected by,” O’Leary says.

One question the working group is considering is “do either of the two different aluminum adjuvants increase the risk of asthma?” according to a document outlining the group’s mandate.

Most public health experts say there’s no good evidence that aluminum adjuvants are unsafe and ample evidence that they pose no real concern. In fact, a large Danish study recently debunked any danger. People are exposed to far more aluminum on a daily basis from food, consumer products and their surrounding environment than from vaccines.

In addition to concerns over asthma, critics claim aluminum can also increase the risk for other health problems, including autism and attention deficit hyperactivity disorder.

“Based on large, long-term studies and immunology research, there is no evidence that vaccines cause either allergies or autoimmune disorders e.g., Type 1 diabetes, rheumatoid arthritis, multiple sclerosis, systemic lupus,” Dr. Frank Virant, president of the Board of Directors at the American Academy of Allergy, Asthma & Immunology, wrote in an email to NPR.

But removing aluminum from vaccines would render them ineffective, and there are no substitute vaccines ready to go. It could take years to develop reformulated replacements.