The Centers for Disease Control and Prevention announced Monday an unprecedented overhaul of the childhood vaccine schedule that recommends fewer shots to all children.
Under the change — effective immediately — the vaccine schedule will more closely resemble Denmark's, recommending all children get vaccines for 11 diseases, compared with the 18 previously on the schedule.
Senior Health and Human Services officials said the changes are meant to restore trust in public health that spilled over from the Covid pandemic.
"The loss of trust during the pandemic not only affected the COVID-19 vaccine uptake. It also contributed to less adherence to the full CDC childhood immunization schedule, withlower rates of consensus vaccines such as measles, rubella, pertussis, and polio," reads the scientific assessment the agency based its decision on.
The assessment said "there is a need for more and better science" on vaccines — though the new schedule does not say there are specific vaccines children shouldnotget.
Dr. Yvonne Maldonado, a professor of global health and infectious diseases at Stanford University, said there was an "incredible lack of transparency" behind the new schedule.
"There are no data, no papers, no discussions at all that are cited in this quote-unquote exhaustive search. So we have no idea who made these decisions and why they were made now," she said.
Dr. Jake Scott, an infectious diseases specialist at Stanford Medicine, said the change could have a dramatic effect on vaccine uptake.
"It's really the most significant weakening of childhood vaccine recommendations, I would say, in modern American history," he said.
In practice, however, not much will change for parents who want their children to continue to get all of the vaccines previously recommended. Insurance will continue to cover the shots.
"The best case scenario is that nothing will change," said Dr. David Margolius, the director of public health for the city of Cleveland. "The worst case scenario is that this causes more confusion, more distrust, lower vaccination rates, and then just this trend of political parties and ideologies determining which vaccines people should get."
There's no "rigor or reason" to reduce the number of shots just because another country did it, Margolius said. "It just doesn't make sense."
Dr. Helen Chu, an infectious disease professor at the University of Washington, said in an email: "The abrupt change to the entire US childhood vaccine schedule is alarming, unnecessary, and will endanger the health of children in the United States."
What's changed?
In Denmark, vaccines for the flu, Covid, RSV, chickenpox, hepatitis A, rotavirus and meningitis are not included in the childhood schedule. Denmark also recommends some shots — including polio, diphtheria, tetanus and whooping cough — on a slightly different timeline than the U.S.
The CDC said it will continue to recommend that all children get vaccines for measles, mumps, rubella, polio, pertussis, tetanus, diphtheria, Haemophilus influenzae type B (Hib), pneumococcal disease, HPV and chickenpox.
Other vaccines, however, will be recommended for "high-risk groups" or recommended based on so-called shared clinical decision-making. Vaccines recommended for high-risk groups are shots for RSV, hepatitis A, hepatitis B, dengue and two types of bacterial meningitis.
The vaccines recommended based on shared clinical decision-making are for rotavirus, the flu, hepatitis A, hepatitis B and bacterial meningitis. The Covid vaccine was moved to shared decision-making last year.
A senior HHS official said that all vaccines recommended as of the end of 2025 — before this schedule change went into place — will remain available and covered by Affordable Care Act plans and federal insurance plans, including Medicaid, the Children's Health Insurance Program and the Vaccines for Children program.
The childhood vaccine schedule is a set of recommendations on the timing of vaccinations. It's not a mandate, but is used to guide what vaccines are covered by insurance and are needed to attend daycare and public schools. States determine which vaccines are required for school attendance and have historically relied on the CDC schedule. It's usually reviewed annually by the CDC's Advisory Committee on Immunization Practices (ACIP) and updated based on the latest scientific evidence.
"The ACIP should have done this work," said Maldonado, who was fired from ACIP along with 16 of her colleagues, including Chu, in June. Kennedy replaced the panel with a group that has largely expressed skepticism of vaccines.
Going from a universal recommendation to shared decision-making or a recommendation only for high-risk groups will make some deadly diseases seem benign, Maldonado said.
"The ones that really stand out to me are RSV and influenza," she said."The vast majority of the kids who get these diseases, wind up in the hospital, wind up in the ICU, are children who are previously healthy. So where is their risk factor?"
Dr. Ofer Levy, director of the Precision Vaccines Program at Boston Children's Hospital, said there is both some logic and limitations to modeling the U.S. schedule off of European countries.
"I wish they would have convened the [Food and Drug Administration] and the CDC committees to discuss this approach," Ofer said. "Because not all of this was really hashed out in a discussion that was available for the public to listen to and participate in."
Margolius said going from 18 to 11 shots doesn't limit a child's exposure to infectious diseases, a risk that's different for people in the U.S. than it is for those in Denmark.
"The population of Denmark is 6 million individuals," he said. "It'd be like cutting Ohio in half and determining which infections we should vaccinate against based on half the population of Ohio."
Why Denmark?
Health Secretary Robert F. Kennedy Jr., an anti-vaccine activist, has said he believes children in the U.S. receive too many vaccines, falsely saying on multiple occasions that kids get as many as 90 doses before age 18. As health secretary, he has moved to limit vaccines for kids, including removing a recommendation for the Covid shot. Last month, the CDCrolled back a decades-long recommendationthat all newborns get their first dose of the hepatitis B vaccine within 24 hours — a move experts said could lead to a resurgence of infections.
In December, Dr. Tracy Beth Hoeg, the acting director of the Food and Drug Administration's Center for Drug Evaluation and Research who has been critical of the Covid shot, gave a presentation on the Danish vaccine schedule duringa CDC vaccine advisory committee meeting.
The presentation by Hoeg — who holdsdual citizenship in the U.S. and Denmark— suggested fewer vaccines may reduce children's exposure to aluminum, an ingredient used in shots to boost the immune response and a target of anti-vaccine groups. A major study from Denmark,published in July, found that aluminum exposure from vaccines is not harmful. Kennedydemanded the journal retract the study, calling it "a deceitful propaganda stunt by the pharmaceutical industry"; the journal did not issue a retraction.
Shortly after the meeting ended,President Donald Trump directed health officialsto review U.S.childhood vaccinationrecommendations and align them with the "best practices" from other developed countries — including Denmark.
Anders Peter Hviid, the senior author of the Danish study on aluminum in vaccines and a professor in the department of epidemiology research at Statens Serum Institut in Denmark — that country's equivalent of the CDC — wrote in an email in December that Denmark has a more homogeneous population than the U.S., with greater trust in public health institutions, universal and free health care and lower rates of serious outcomes from infectious diseases that it doesn't vaccinate against but the U.S. does.
Denmark's robust public health system, for example, makes it much easier for the country to test pregnant women for hepatitis B and ensure that babies born to women test positive are vaccinated against the disease. A similar approach, now endorsed by the CDC, had not been successful in the U.S. at cutting infection rates in children.
Denmark's vaccination schedule is not set in stone, however. Meeting summaries from the Danish Vaccine Council — an expert panel that advises Denmark on vaccine recommendations — from November, 2024 suggest growing interest in reassessing rotavirus, chickenpox and hepatitis B vaccinations.
In October, the Danish government began recommending RSV vaccination for pregnant women. The vaccine council is also considering the RSV antibody shot for infants. The shot was approved in the European Union in 2022.
Hviid said under the proposed changes, outbreaks for disease currently rare in the U.S. "will only get worse."
"Derecommending will likely lead to lower uptake," he said, "leaving more children exposed to infectious disease, both among those that choose not to get vaccinated and those too young or in vulnerable populations that depend on indirect protection through herd immunity."