This is a KFF Health News story.

Florida plans to end nearly a half-century of required childhood immunizations against diseases that have killed and maimed millions of children. Many critics of the decision, including doctors, are afraid to speak up against it.

With the support of Republican Gov. Ron DeSantis, Surgeon General Joseph Ladapo on Sept. 3 announced his plan to end all school-age vaccination mandates in the state.

“Every last one of them is wrong and drips with disdain and slavery,” he told a cheering crowd of vaccination foes in Tallahassee. “Who am I, as a government or anyone else,” he said, “to tell you what you should put in your body?”

History shows that mandates increase the use of vaccines. Lower vaccination rates will mean increased rates of diseases like measles, hepatitis, meningitis, and pneumonia — and even the return of diphtheria and polio. Many of these diseases threaten not just the unvaccinated but also those they come in contact with, including babies and older people with weakened immunity.

But that scientific fact is being left unsaid in Florida. Health officials have largely been silent in the face of Ladapo’s campaign — and not because they agree with him. The University of Florida muzzled infectious disease experts, said emeritus professor Doug Barrett, formerly the university’s chief of pediatrics and senior vice president for health affairs.

“They’re told not to speak to anyone without permission from supervisors,” he said. University spokespeople didn’t respond to requests for comment.

County-level Department of Health officials across the state got the same message, said John Sinnott, a retired professor at the University of South Florida who is friends with one of the county health leaders.

Sarasota County’s health department referred a reporter to state officials in Tallahassee, who responded with a statement that vaccines will “remain available” to families who want them. The state did not respond to other requests for comment or for an interview with Ladapo.

Many pediatricians are silent, too, at least in public.

“A lot of them don’t take a strong stance on whether kids need to be vaccinated,” said Neil Manimala, a urologist and the president-elect of the Hillsborough County Medical Association. “They don’t want to lose business. And there are enough anti-vax people who can lambaste you on Google, spreading stories about clinicians who ‘want to instill the poison jabs.'”

History of modern vaccine mandates

Several states ended vaccination mandates early last century when smallpox was the only widely given vaccine, said historian Robert Johnston of the University of Illinois-Chicago. None has done so since other vaccines were added to the schedule. (Routine smallpox vaccination ended in 1972).

In the 1970s, persistent measles outbreaks provoked officials to strengthen child protection with enforced school mandates in every state. Today the partisan split on vaccine policy in the wake of the covid outbreak has changed the equation. This is nowhere more the case than in Florida, although legislators in Texas and Louisiana are also considering ending mandatory vaccination, and Idaho enables parents to get an exemption just by asking for it.

“This is really going to be a watershed moment for families who already were not sure they want to do vaccines and now are being told they don’t need them,” said Jennifer Takagishi, vice president of the Florida branch of the American Academy of Pediatrics.

It’s hard to know how fast vaccine-preventable diseases might return if Florida ends its mandates — or how the public will respond. Asked in an interview whether his office had modeled disease outcomes before his September announcement, Ladapo said “Absolutely not.” Parental freedom of choice isn’t a scientific matter, he said. “It’s an issue of right and wrong.”

Ladapo’s Department of Health did not respond a month later when asked whether it was making contingency plans for outbreaks. During a 2024 measles outbreak in Broward County, Ladapo sent parents a letter granting them permission to send unvaccinated children to school, defying the science-supported advice from the federal Centers for Disease Control and Prevention.

In 1977, a measles epidemic that killed two children in Los Angeles County spurred a dramatic crackdown on vaccine-shunning across the country. But during an epidemic this year that killed two Texas children and 14 people in Mexico, Republican Gov. Greg Abbott of Texas signed a bill making it easier for parents to opt out of getting required shots.

“When are we going to have enough of a groundswell of people dying or becoming severely ill that leads people to push back and say, ‘No, no, we want the vaccines?'” Takagishi said. “I don’t know if we know the tipping point yet.”

“I don’t have the answer,” said Emory University emeritus professor Walter Orenstein, who worked on measles for many of his 26 years at the CDC and led the agency’s immunization program from 1988 to 2004. “Measles resurgences created the political will to support our overall immunization program. For some reason it hasn’t worked this time. It’s just sad.”

Youngsters in Florida are already among the least vaccinated in the nation, because of relatively lax enforcement, the post-covid backlash against shots, and the libertarian attitude of state officials. Statewide, only about 89% of kindergartners are fully vaccinated, with Sarasota County having the lowest rate, at about 80%. To be safe from the spread of measles, a community must be 95% immunized.

With Health and Human Services Secretary Robert F. Kennedy Jr. cutting vaccine research, filling the health agency with anti-vaccine activists and spreading doubt about vaccination’s safety and value, little stands in the way of decisions by Florida officials that are likely to cause rates to sink further.

Ladapo’s department is ending mandates for shots against hepatitis B, chickenpox, and the bacteria causing meningitis and pneumonia. Early next year, the Florida Legislature is expected to take up reversal of a 1977 law requiring kids at school and day care to be vaccinated against seven other diseases that can kill children: whooping cough, measles, polio, rubella, mumps, diphtheria, and tetanus.

After measles, which disease returns next?

In the face of these attacks, scientists are attempting to predict which diseases are likely to make a resurgence and when.

A study published in April by Stanford epidemiologist Mathew Kiang and colleagues estimated that even at current vaccination levels, measles, declared eliminated from the United States in 2000, is likely to become a routine illness again. If measles vaccination rates drop by an additional 10%, there could be an average of about 450,000 cases yearly, with hundreds of deaths and cases of brain damage.

But the study may exaggerate the threat, said Shaun Truelove, an epidemic disease modeler at Johns Hopkins University who said he’s worried about losing public trust with alarmist predictions. Still, he said, an intensification of measles outbreaks seems certain. The country is already in the midst of its worst measles year in three decades, with more than 1,500 cases and current outbreaks in South Carolina and Minnesota.

“You don’t really need to model measles if vaccines stop,” Truelove said. “In the pockets where there are outbreaks, every kid who isn’t vaccinated will get infected.”

Measles is the “canary in the coal mine” for other vaccine-preventable diseases, said Sal Anzalone, a pediatrician with Healthcare Network in Naples, Florida. “When you start seeing measles, there’s more to come behind that.”

People who want vaccinations will still be able to get them if mandates are eliminated, Ladapo has said.

But the state’s message confuses parents, especially the poor and underserved, Anzalone said. It’s typically hard for them to get children to appointments unless they have to, he said, noting that 80% of his patients are insured through Medicaid. If policies put more of the payment burden on parents, fewer will vaccinate, he said.

And if vaccinations fall and infections increase, children won’t be the only people affected. Cancer patients and people in Florida’s numerous elderly communities would be at risk. Schools and businesses would be disrupted. Disease could disrupt the tourism industry, which brought 143 million people to the state last year. (The Florida Chamber of Commerce did not respond to requests for comment.)

“Infectious diseases don’t stop with the people who say they are willing to bear the risk,” said Meagan Fitzpatrick, a University of Maryland vaccinologist. Because of their unpredictable spread, she said, “with an infectious disease, vaccination is never an individual choice.”

Clinicians fear that an end to mandates could allow hepatitis B, a chronic liver disease, to return with force, since an estimated 2 million Americans carry the virus. They also foresee a return to the days when infants with high fever had to undergo a painful and risky lumbar puncture and blood draw to rule out meningitis, as well as a blood infection caused by the bacteria Haemophilus influenzae type B that routine vaccination has prevented since the 1990s.

Barbara Loe Fisher, who co-founded the modern movement against vaccine mandates in the early 1980s after her son suffered a reaction to the pertussis vaccine then in use (and since replaced with a safer shot), is skeptical that Floridians will abandon vaccination en masse, despite the end to mandates.

Fisher, president of the National Vaccine Information Center, moved from Virginia to southwestern Florida in 2020. She said she believes that vaccine injuries are undercounted and that children are vaccinated without informed consent. She acknowledged that mandates have increased coverage but said their removal will increase trust in public health and medicine.

“It is time to allow biological products like vaccines to be subject to the law of supply and demand,” she said, “just like any other product sold in the marketplace.”

Sinnott, for his part, anticipates measles will come roaring back, along with intensified whooping cough, influenza and COVID outbreaks.

“They think nothing will happen. Maybe they’re right,” said Sinnott, the retired professor. “It’s an experiment.”

Polio could return, and that is not an abstraction for Sinnott, 77.

He was 7 years old when he contracted the disease, spending six months in a wheelchair. In recent years he’s suffered from post-polio syndrome — difficulty swallowing and tightness and pain in his limbs.

The first polio vaccine was licensed in 1955, the year he got sick. “I remember one time my mother telling me, ‘The line was too long,'” he said.

Sinnott forgives his parents, and parents today who waver on vaccination. He’s less tolerant of certain public health leaders. They should know better, he said.