Removing Florida's school-entry vaccine requirements could set off a measles epidemic within three to five years, with peak infection rates exceeding any U.S. year since 1977, according to a mathematical model published in PNAS on Sept. 28. The United States counted 57,345 measles cases in 1977.
The projection is a worst-case scenario, not a forecast of what will happen. Florida has not removed its measles vaccine requirement for school entry. But for parents weighing school rules, exemptions, and a year of record measles activity, the model puts numbers on what could happen if coverage keeps slipping.
Model Conditions Behind the Worst-Case Projection
The University of Maryland team, led by doctoral student Alice Oveson and mathematician Abba Gumel, built a model of measles spread among children and adults in Florida. In the worst case, kindergarten vaccination falls to about 82%, WUSF reported.
Under that scenario, epidemic peaks reach 260 to 315 measles cases per 100,000 children, with adult rates about half as high. The researchers projected hundreds of child deaths within five years in that case. Every one of these figures is a projection that depends on the model's assumptions about vaccination and contact.
"Small reductions in child vaccination rates can lead to disproportionately large increases in the scale of outbreaks," Oveson said in a University of Maryland release. The study found that vaccinating one child was about three times more effective at reducing transmission than vaccinating one adult. The work was funded by the National Science Foundation.
Gumel pointed to how quickly the disease has returned. "Measles is one of the most contagious human pathogens, and we've seen a striking 650% increase in cases just between 2024 and 2025," he said. The university also cited national survey data showing that 16% of parents were not confident the MMR vaccine is safe and 18% fully opposed school-entry MMR mandates.
Florida's MMR Requirement Remains in State Law
Florida Surgeon General Joseph Ladapo called in September 2025 for ending all school vaccine mandates. In August, he approved a proposed state health department rule that would drop four vaccines from school requirements: hepatitis B, chickenpox, Hib, and pneumococcal. The rule has not taken effect, and a physicians group has requested a hearing on it. MedicalDaily reported that the MMR requirement is set by state statute, so only the Legislature can remove it.
Coverage is already below the 95% level generally needed to stop measles spread. About 88.9% of Florida kindergarteners were fully vaccinated in the 2025-26 school year, and Sarasota County was at 79%, according to WUSF. Florida's vaccine exemption rate of 5.9% exceeds the national average of 4.2%, the university said.
Florida has documented 162 measles cases in 2026 and no deaths. Before the vaccine, measles killed about 500 Americans a year, according to WUSF. Nationally, the CDC counted 3,659 cases as of Sept. 24, MedicalDaily reported this week, the highest total in decades.
Outside Expert Questions the Method
Ira Longini, a University of Florida biostatistician who was not involved in the study, disputed how the model handles contact between people. "A simple, deterministic random mixing model with just children and adults is not able to make accurate projections of the number of cases and deaths over time because people simply do not mix randomly on a state level," he told WUSF.
In real life, measles clusters in schools, churches, and neighborhoods with low vaccination rates. That can make outbreaks more intense in some places and less likely in others than a statewide average suggests. Longini agreed with the broader concern, saying, "Yes, we will see more cases and deaths in both children and adults due to increasing sporadic outbreaks as coverage in children declines and even in vaccinated adults."
Oveson argued that the policy signal itself carries risk. Eliminating the school mandate "would suggest that vaccination is unnecessary, which is simply inaccurate and dangerous," she said.
Protection Steps for Florida Families
Parents can check their children's records to confirm two doses of the MMR vaccine, usually given at 12 to 15 months and again at 4 to 6 years. The shots are available at pediatricians' offices, pharmacies for older children, and county health departments, often at low or no cost through the federal Vaccines for Children program.
Measles often begins with high fever, cough, runny nose, and red, watery eyes, followed by a rash that spreads from the face downward. Families who suspect measles should call a clinic before arriving, so staff can avoid exposing others in the waiting room.
Infants too young for the vaccine and children with weakened immune systems depend on high community coverage. For the MMR requirement to change, the Florida Legislature would have to act. Its 2027 regular session begins March 2.
Key Questions Answered
What did the model project? A worst-case measles epidemic within three to five years, with peak rates above any U.S. year since 1977, if Florida kindergarten vaccination falls to about 82%.
Has Florida dropped its measles vaccine requirement? No. MMR is required by state statute, and only the Legislature can change it.
Which vaccines is Florida moving to drop? Hepatitis B, chickenpox, Hib, and pneumococcal, through a proposed health department rule that has not yet taken effect.
Do other experts agree with the model? University of Florida biostatistician Ira Longini said the model cannot accurately project case numbers, though he expects more outbreaks as coverage falls.
How many measles cases has Florida had this year? 162, with no deaths, according to WUSF.
How can parents protect children? Confirm two MMR doses and call a clinic before visiting if measles is suspected.
Who is most at risk? Unvaccinated children, infants too young for the vaccine, and people with weakened immune systems.
Published by Medicaldaily.com
