US Measles Cases Hit a 35-Year High With Florida Among the Top Five States

The United States has recorded more measles cases in 2026 than in any year since the early 1990s, and Florida is among the states driving the total. Federal data showed 2,318 confirmed cases nationwide as of July 23, surpassing the 2,289 cases recorded for all of 2025 and marking the highest single-year count since the resurgence period of 1989 to 1991.

Florida has reported 141 confirmed cases in 2026, ranking fifth among states. That figure represents an extraordinary increase from the eight cases the state recorded in all of 2025 and the 11 cases in 2024.

Public health officials have attributed the national surge to declining vaccination coverage. Of the 2,318 confirmed cases nationally, 2,153, or 93 percent, are associated with identified outbreaks rather than isolated travel-related infections, and 35 new outbreaks have been reported this year.

How measles spreads and why it spreads fast

Measles is among the most contagious infectious diseases known. The virus spreads through the air when an infected person breathes, coughs, or sneezes, and it remains viable in the air and on surfaces for up to two hours after that person has left a space.

The transmission characteristics are what make it distinctive. In a fully susceptible population, one infected person will on average infect somewhere between 12 and 18 others, a figure far above that of most respiratory viruses. That is why measles requires very high population immunity, generally cited at 95 percent, to prevent sustained transmission.

Infected people are contagious for roughly four days before the characteristic rash appears and four days afterward. That pre-rash contagious window is the reason exposures frequently occur in settings including emergency departments, pediatric offices, schools, airports, and retail spaces before anyone knows measles is present.

The illness begins with high fever, cough, runny nose, and conjunctivitis, followed by a rash that typically starts at the hairline and spreads downward. Small white spots inside the mouth, called Koplik spots, can appear before the rash.

The complications

Measles is frequently described as a childhood rash illness, which understates its severity. Roughly one in five unvaccinated people who contract measles in the United States requires hospitalization.

Pneumonia is the most common cause of measles death in young children. Encephalitis, inflammation of the brain, occurs in roughly one in a thousand cases and can cause permanent neurological injury including deafness and intellectual disability.

Measles also causes what researchers call immune amnesia, in which the infection depletes existing immune memory to other pathogens. Children recovering from measles can be more vulnerable to other infections for months or years afterward.

Subacute sclerosing panencephalitis is a rare, invariably fatal degenerative neurological condition that develops years after measles infection, with risk highest for children infected before age two.

Where Florida's cases are

Florida's 141 cases place it fifth nationally, behind states with larger identified outbreaks. The largest clusters in 2026 have been centered elsewhere, with South Carolina exceeding 600 cases and Utah reporting more than 400 in an ongoing outbreak.

Florida has recorded outbreaks in multiple settings this year, including a campus-associated outbreak that grew over a period of weeks. Central Florida reported its first case of the year earlier in 2026.

The Florida Department of Health maintains reportable disease surveillance and publishes case data through Florida Health CHARTS. County health departments conduct contact tracing when cases are identified, notifying people who may have been exposed at specific locations and times.

Measles is a reportable condition in Florida, meaning clinicians and laboratories are required to notify public health authorities on identification. That reporting requirement is what makes case counts reasonably reliable, in contrast to conditions with substantial undiagnosed transmission.

Vaccination and what it means for Florida families

The measles, mumps, and rubella vaccine is highly effective. Two doses provide approximately 97 percent protection against measles, and one dose provides approximately 93 percent. The standard childhood schedule calls for the first dose at 12 to 15 months and the second at 4 to 6 years.

Because the first dose is not given until after the first birthday, infants under 12 months are among the most vulnerable population. They depend on community immunity for protection, which is the mechanism that fails when vaccination coverage declines.

Adults who received two documented doses are considered protected. Adults born before 1957 are generally presumed immune due to near-universal childhood infection before the vaccine era. Adults uncertain of their status can have immunity confirmed through blood testing or can receive vaccination, which carries no risk from repeat dosing.

Families planning international travel, or travel to areas with active outbreaks, should confirm vaccination status in advance. An accelerated schedule is available for infants 6 to 11 months traveling internationally, though those doses do not count toward the routine two-dose series.

Florida school entry requirements include measles vaccination, with medical and religious exemptions available under state law. Exemption rates are one of the factors public health researchers track when assessing outbreak vulnerability at the school and community level.

The elimination status question

The United States declared measles eliminated in 2000, meaning there was no continuous transmission of the virus within the country for more than 12 months. Cases since then have originated with international importation, with subsequent spread among susceptible people.

Sustained transmission chains lasting more than 12 months would jeopardize that elimination status. With 2026 case counts at a 35-year high and outbreaks numbering 35 across the country, public health officials have raised that concern directly.

Losing elimination status would be a symbolic setback with practical implications for international travel guidance and for public health resource allocation. It would also reflect an underlying reality about population immunity that the case counts already demonstrate.

How outbreaks are contained

Public health response to a measles case follows an established protocol. Once a case is laboratory-confirmed, health department staff conduct contact tracing to identify everyone potentially exposed during the infectious period, which extends from four days before the rash appears through four days after.

Exposed people who are not immune are advised to quarantine for a period that accounts for the incubation period, which can extend up to 21 days. That is a substantial disruption for families, schools, and workplaces, and it is a significant part of the public cost of each case.

Post-exposure prophylaxis is available. Vaccination within 72 hours of exposure can prevent or reduce the severity of illness, and immune globulin within six days provides protection for people who cannot be vaccinated, including infants and immunocompromised individuals.

Schools and child care facilities frequently exclude unvaccinated students during an outbreak, a public health authority that exists in Florida law and that districts exercise on the direction of health officials. That exclusion is what converts a vaccination decision into an immediate practical consequence.

The cost of a single case

Studies of measles outbreak response have consistently found that each confirmed case generates public health costs in the tens of thousands of dollars, driven by staff hours spent on contact tracing, laboratory testing, notification, and vaccination clinics.

Those costs fall on county health departments operating with fixed budgets, which means that outbreak response displaces other public health work. Staff assigned to a measles investigation are not conducting the routine surveillance, inspection, and prevention activities that constitute their normal function.

Hospital costs add to the total. With roughly one in five unvaccinated measles patients requiring hospitalization in the United States, and with pediatric hospitalizations frequently involving intensive care, the medical expenditure per outbreak is substantial.

The comparison that public health officials draw is with the cost of vaccination, which is a fraction of outbreak response per person protected and which is covered by insurance and by the federal Vaccines for Children program for eligible children.

What Florida schools require

Florida requires proof of immunization for school entry, documented on a state certificate issued by a health care provider or county health department. The measles, mumps, and rubella vaccine is among the required immunizations for kindergarten entry.

Exemptions are available under Florida law on medical grounds, certified by a physician, and on religious grounds, documented through the county health department. Exemption rates vary substantially by county and by individual school.

Because measles requires very high population immunity to prevent transmission, generally cited at 95 percent, schools with exemption rates above a few percent can fall below the threshold at which an introduced case is contained. That is the mechanism behind school-centered outbreaks.

Parents can verify their children's immunization records through Florida SHOTS, the state immunization registry, which providers and county health departments can access. Families uncertain about status should confirm before the school year begins in August.

Where to find current figures

National case counts are published by the Centers for Disease Control and Prevention and updated regularly through the year. Florida-specific surveillance data is available through the Florida Department of Health and Florida Health CHARTS.

County health departments issue local exposure notifications identifying specific locations and time windows where transmission may have occurred, which is the most actionable information for residents in an affected area.

What's next

Summer travel season, followed by the return to school in August, represents the period of highest transmission risk for the remainder of the year. Both concentrate susceptible people in shared spaces.

The Centers for Disease Control and Prevention updates national case counts regularly, and the Florida Department of Health publishes state surveillance data. County health departments issue exposure notifications when specific public exposures are identified.

Parents with questions about their children's vaccination status should contact their pediatrician or county health department, both of which can access immunization records through Florida SHOTS, the state immunization registry. Anyone with symptoms consistent with measles should call ahead before visiting a medical office, so that staff can prevent exposure to others in the waiting area. The Florida Press will continue reporting on the outbreak.