A new federal directive on childhood vaccines is putting federal policy at odds with leading medical organizations.
President Donald Trump’s Aug. 10 executive order calls for reducing the number of vaccines routinely recommended for all children, separating the measles, mumps and rubella vaccine into individual shots and, when possible, spacing childhood vaccines across separate medical visits. Major medical organizations have pushed back, saying the changes are not supported by scientific evidence and could leave children vulnerable to preventable diseases. In 2026, the American Academy of Pediatrics began maintaining its own childhood immunization schedule — endorsed by 12 leading medical and health organizations — that differs from federal recommendations.
For parents, the split raises a fundamental question: Whose advice should they trust?
Jennifer Layden, MD, PhD, associate dean for practice and professor at Washington University in St. Louis’ Bursky School of Public Health, brings a unique perspective to that question. An infectious diseases physician and epidemiologist, Layden has held public health leadership positions at the state, local and federal levels. She served as Illinois’ state epidemiologist and chief medical officer, providing scientific leadership to the state’s immunization program and overseeing responses to measles and other outbreaks. She later directed Chicago’s COVID-19 response and spent five years at the Centers for Disease Control and Prevention, where she oversaw national vaccination efforts and served as a scientific adviser to the CDC director.
Here, Layden discusses conflicting vaccine guidance.
How are changes to the vaccine schedule typically made, what safeguards are in place and how is this different?
Vaccine recommendations and schedules emerge from a complex process involving numerous experts, extensive review of scientific studies and ongoing monitoring of impact and safety. The Advisory Committee on Immunization Practices, or ACIP, was established in the 1960s to provide outside expert guidance to the CDC and federal government. In evaluating vaccines, the committee considers the burden and severity of disease, vaccine efficacy and effectiveness, safety, economic analyses and implementation issues.
Numerous systems continue to monitor vaccine safety after recommendations are made, allowing ACIP to reevaluate and revise its guidance as new information emerges. Two important safeguards are the involvement of external experts and this continuous review of new evidence. Recommendations do not come from the CDC or another federal agency acting alone.
It is also important to distinguish federal vaccine recommendations from school vaccination requirements. States determine which vaccines children must receive to attend school; neither the CDC nor another federal agency has the legal authority to impose those requirements.
Are the stakes of changing timing different for babies than older children?
Yes and no. Babies have less natural protection against infections and cannot receive certain vaccines before age 1, making them particularly vulnerable. Missing or delaying a recommended vaccine extends the period when they are at risk.
The stakes are different for older children. Some vaccines are timed to protect against infections that pose particular risks at certain ages, such as meningitis in the late teen years. As confusion about vaccine recommendations grows, so does the risk that children will miss or delay safe, lifesaving vaccines.
The federal directive calls for spacing vaccines across separate visits. What are the consequences of asking families to make more appointments?
That is an incredibly hard ask. As a physician, I think parents who want that flexibility should have it. But requiring separate visits places a hardship on many families. More appointments can mean more time off work and school, lost wages and additional costs for transportation, parking and medical visits. It also increases the likelihood that vaccines will be missed.
The administration says more vaccine choices give parents greater autonomy. What do we gain or potentially lose with that approach?
That is an important consideration. If parents feel strongly about spacing vaccines and can manage the additional time and cost, that seems reasonable, assuming they understand the potential risks of delaying vaccination.
But if we reduce the schedule or recommend that vaccines be spaced out, we may actually limit autonomy for a whole segment of our population. There is a way to make recommendations that meet the population’s needs while still providing flexibility. Ideally, we should find that balance.
With federal and medical vaccine guidelines at odds, how should families decide whom to trust?
My concern is that families and parents are incredibly confused, and confusion can lead to mistrust. I always recommend that families discuss options with their doctor or other healthcare provider, who can help them understand the recommendations and make informed decisions for their children.
Could vaccine standards vary considerably by state? What would that mean for the country’s ability to prevent outbreaks?
Vaccine laws and school requirements are set at the state level. Historically, most states have followed ACIP recommendations and incorporated them into state policy. Over the past year, however, we have seen some states instead look to medical associations or their own health departments for guidance. There is absolutely a likelihood that we will see variation across states.
That poses challenges in a country where people travel, work and live in different states. Missouri alone borders eight states. If neighboring states have different vaccine requirements, we could see significant differences in vaccination rates — and ultimately disease burden — between counties separated only by a state line. It also could make responding to outbreaks much more difficult.
What is happening now that worries you most — but that the public may not yet understand?
There are two things.
First, the continued loss of trust in public health and healthcare. Confusion can lead to mistrust, and we are creating an environment in which parents, families and individuals face even greater confusion.
Second, we may not see the consequences of lower vaccination rates for some diseases for years. We are already seeing a rise in measles, and I expect that to continue. But with diseases such as hepatitis B; meningococcal disease, which can cause deadly meningitis; or HPV, which can cause some types of cancer, the impact will not be immediate. It could take years for the consequences to become apparent.
