Last week, the Department of Health and Human Services announced changes to the national immunization schedule. The announcement marks another step in the unraveling of the legal and scientific architecture that has long governed vaccine policy in the United States.
For decades, U.S. vaccine policy rested on a disciplined legal and scientific structure. Federal agencies evaluated evidence through established expert processes. National immunization recommendations reflected that review. States, exercising their constitutional authority over public health, largely aligned their vaccination laws and practices around those federal standards. The result was not uniformity for its own sake, but coherence: a shared understanding of what routine, collective vaccination meant, and why it was vital for the public good.
That coherence is now collapsing. We are entering the era of vaccine federalism, and it will not be good.
HHS’s latest revision to the national immunization schedule is not an isolated event. It is the latest in a series of actions by health secretary Robert F. Kennedy Jr. that have steadily dismantled the processes and norms that once anchored vaccine policy. Longstanding recommendations for routine childhood vaccines have been weakened or reframed, not because the underlying science had changed, but because the objective, evidence-based mechanisms designed to evaluate that science have been sidelined.
Federal vaccine recommendations derive their authority from method. Traditionally, advisory committees staffed with the nation’s leading scientists weigh evidence publicly. Conflicts are rare and disclosed. Rationales are explained. That structure is what allows federal guidance to serve as a credible reference point for states, clinicians and parents. When the secretary bypasses or distorts that structure, the guidance loses its claim to legitimacy. Public trust wanes.
States have been responding to this erosion for some time. This did not begin with the latest schedule. Earlier federal actions already signaled that national vaccine standards were becoming unstable. Some states moved to preserve evidence-based schedules by relying on professional medical societies or by reinforcing existing laws that relied on previously reputable federal guidance. Others moved in the opposite direction, using federal ambiguity to justify loosening requirements and politicizing vaccination policy.
The result is an accelerating divide.
Routine vaccines that once carried the same status across jurisdictions are now treated differently depending on political geography. In some states, they remain the unquestioned standard of care. In others, they are recast as controversial. These are not minor regulatory differences. They are fundamentally different answers to the question of whether routine vaccinations against diseases, long established as serious threats to health and life, are as important in Florida and Texas as they are in California and New York.
The secretary’s repeated and overt politicizing actions are widening this wedge.
Each change that departs from established scientific process gives states further justification to break from one another. Each reframing of routine vaccination as an individual choice, and negotiable, reinforces the idea that vaccine standards are political rather than evidentiary. Over time, this divide compounds. Standards of care diverge. State laws diverge. Federal guidance becomes less a unifying reference and more a catalyst for fragmentation.
This is not how federalism under our Constitution is supposed to work.
Federal vaccine policy was never meant to dictate state law. It was meant to provide a stable evidentiary foundation upon which states could rely. When that foundation erodes, states are not exercising independent judgment grounded in science. They are reacting to the absence of a credible national standard. What replaces coordination is polarization.
Vaccine policy now tracks political identity more closely than epidemiology.
States that align politically with the secretary’s approach are reshaping their vaccine laws and messaging accordingly. Many states are new enacting or widening already broad religious and conscientious exemptions. Others, like Florida, are eliminating vaccine requirements as a condition of school entry. States that reject the secretary’s unscientific recommendations are entrenching their own standards in opposition. The nation is drifting toward parallel immunization regimes, divided not by disease risk but by ideology.
This fracture has direct implications for vaccines themselves and for the public’s health.
The unavoidable result of this fragmentation is that children’s health will now depend on geography. In states that preserve evidence-based vaccine schedules, high coverage will continue to prevent infections and avert hospitalizations and deaths. In states that weaken routine immunization standards, vaccination rates will fall, preventable diseases will resurge, and more children will become seriously ill and die. This is not speculation or rhetoric; it is the well-documented consequence of reduced vaccine uptake. Federal leadership once minimized these disparities by anchoring states to the same scientific baseline. As that anchor is cut loose, the United States is accepting a future in which some states protect children from known risks while others expose them to avoidable harm.
And even in states that maintain a full childhood vaccination schedule driven by science, people will be at risk. Mass travel will continue unabated. (Think about families traveling to Disney World in Orlando, Fla.) Nationally, we will have lost herd immunity. People who are most vulnerable like those with immune dysfunction or the elderly will be exposed to deadly diseases, irrespective of where they live. The social safety net for infectious diseases will crumble.
Vaccination works when expectations are clear and consistent. Parents hear the same message from pediatricians and public health authorities within their states. Clinicians know what constitutes routine care. Public health agencies know which vaccines they are expected to promote and protect. As those expectations splinter, uptake declines and preventable disease gains ground. This is not theoretical. It is already happening.
What makes this moment particularly dangerous is that it is being driven from the top.
When federal leadership undermines vaccine process and precedent, it pushes states further down diverging paths. With each deviation, signals are repeated and the idea of a national immunization standard becomes increasingly incoherent.
If this trajectory continues, the United States will no longer have a single vaccine policy framework. It will have a set of competing regimes, each claiming legitimacy, none capable of commanding broad trust. That is not pluralism. It is collapse.
Vaccine policy depends on evidence, process, and consistency. Strip those away, and what remains is politics deciding which children are protected and which are not. That is not a system worthy of public health — and history will take note.
Richard Hughes IV is a partner with the law firm Epstein Becker Green and a professorial lecturer in law at the George Washington University Law School. He previously served as vice president of public policy at Moderna. Lawrence O. Gostin is distinguished professor of global health law at the O’Neill Institute, Georgetown University Law Center, and director of the WHO Center on Global Health Law.