Experts said the policy will lead to more illnesses and hospitalizations.
Florida's surgeon general made a surprising announcement last week that the state is moving to "end all vaccine mandates."
Dr. Joseph Ladapo said the Florida Department of Health would be working with Gov. Ron DeSantis' office to end all mandates in state law. DeSantis noted that some vaccine mandates would be removed immediately while others would require legislative intervention.
Ladapo said that parents should be able "to choose" what vaccines they want their children to receive or not to receive.
In a statement to ABC News, the Florida Department of Health said the rule change will go into effect 90 days after the Sept. 3 announcement and will include the removal of immunization requirements for the hepatitis B vaccine, chickenpox vaccine, haemophilus influenza type b (Hib) vaccine and pneumococcal conjugate vaccines.
Other vaccines including for poliomyelitis, diphtheria, tetanus, pertussis, measles, mumps and rubella will remain in place unless updated through legislation, according to the state Department of Health.
Several pediatricians and public health experts told ABC News that high vaccination rates and nationwide vaccination campaigns have led to the eradication of diseases, such as polio, and a low number of cases for other diseases compared to decades ago.
They said the removal of mandates -- including those required to attend school -- will likely lead to more infections, hospitalizations and even deaths among children.
Dr. Alok Patel, a pediatrician at Stanford Children's Health and an ABC News contributor, said the short-term impact of Florida removing mandates will be a drop in vaccination rates among school-aged children in the state.
Currently, in Florida, about 89% of children entering kindergarten have received routine childhood immunizations, according to data from the Centers for Disease Control and Prevention (CDC) for the 2024-25 school year.
"We potentially could see that number go even lower," Patel said. "When we remove a mandate, or when things are not deemed as required, you may have vaccine-hesitant parents to look at that and say, 'Okay, great, I don't need to actually do it.'"
He added that removing the mandate makes it easier for children who have barriers to access -- such as lack of insurance or living in a rural area -- to miss vaccines.
"If you have parents who have barriers to getting those vaccines ... and then all of a sudden, they're told you don't need to get them, sometimes the pathway of least resistance is not getting your kid vaccinated," Patel said.
Petel added that lower vaccination rates could potentially set up the return of some diseases, adding that "people need to remember that infectious disease is just a flight away."
Dr. Paul Offit, director of the Vaccine Education Center at Children's Hospital of Philadelphia, said that because Florida is removing mandates -- and potentially other states will follow suit -- a population of children susceptible to diseases is likely to crop up.
He said this is occurring as non-medical exemptions for school-required vaccines among kindergartens are at an all-time high, according to CDC data from 2024-25 school year.
"You may not see it immediately. It may take a couple years, three years, before you really see the impact of this," Offit told ABC News. "I do think that's where we're heading."
Children being susceptible to these diseases because they are not vaccinated means many kids will end up getting sick, hospitalized and even dying, Offit said.
He said children are already dying in the U.S. from vaccine-preventable diseases, including measles, the flu and whooping cough. In Texas, at least two school-aged children died of measles this year, the first deaths in the U.S. in a decade.
"We've had our first child [deaths] from measles ... and flu, you had 266 pediatric deaths from flu this year," Offit said. "We haven't seen a number that big since 2009, since the swine flu pandemic. And what's gone under the radar is pertussis. We have 10 pertussis, or whooping cough, deaths this year in babies. Last year, for the entire year we had two. And this year is not done yet."
Public health experts say states may follow Florida's example, resulting in a patchwork of states with some having strict mandates and others having no mandates.
"I have no doubt that other states will follow Florida's example and make it so that vaccines are no longer mandatory," Offit said. "I think what you're seeing is this sort of 'in the name of medical freedom' [movement], this is the kind of the zeitgeist."
No other states have announced such plans yet, but Patel said more announcements may come if states view removing mandates as politically popular.
All 50 states and Washington, D.C. allow exemptions for school-required immunizations for medical reasons, with some states also allowing religious exemptions or personal exemptions sometimes known as "philosophical exemptions."
Meanwhile, states on the West Coast and several on the East Coast are forming geographic coalitions to offer their own consistent vaccine guidelines, backed by evidence and informed by major national medical groups.
One group, called the West Coast Health Alliance, is made up of California, Oregon and Washington state. The states' governors said in a joint statement that they felt the need to provide their residents with consistent recommendations in the face of inconsistent federal guidance and an erosion of trust in federal health agencies.
Additionally, Massachusetts is speaking with nearby states including Connecticut, Delaware, New York, Pennsylvania and Rhode Island to form a coalition of Northeast states that will similarly issue vaccine recommendations in conjunction with guidance from major medical organizations.
A CDC report published in 2024 found that routine childhood vaccinations have not only prevented illnesses, hospitalizations and deaths but also produced savings in direct and indirect costs.
Among children born between 1994 and 2023, vaccines have resulted in direct savings of $540 billion and societal savings of $2.7 trillion, according to the report. The authors state that infections can lead to costs including for hospital visits, childcare and lost wages.If states remove vaccine mandates, this could raise direct or indirect costs, the experts said.
Offit said he is optimistic that insurance companies will cover the costs of vaccines, because it is cheaper to cover the vaccine than to cover a hospitalization.
Patel agreed, adding that in conversations with parents during cold and flu seasons, while convincing them to get their children the flu shot, he discusses the indirect consequences of not getting the shot.
"[Parents are] like, 'Oh, children don't die from the flu.' And I was like: 'You're right. Like, on average, a healthy child is way less likely to die from the flu,'" Patel said. "But you simply have to look at the numbers of how much school is missed; how much school is missed from children who spread flu to other children; doctor visits; urgent care visits; hospitalizations."
He went on: "Put that all together and you will see just how disruptive something like influenza can truly be—not only on our public health but also on our economy. You add in RSV; add in COVID-19; then potentially add in a lot of other diseases we should be preventing; and you have a setup for a massive public health and economic disaster."