Florida measles cases: Doctors explain what it means for the community after confirming St. Pete case

ST. PETERSBURG, Fla. - Health department officials are closely monitoring the first confirmed case of measles in St. Petersburg after a student at a local high school tested positive for the highly contagious virus.

St. Petersburg Catholic High confirmed this week that a sophomore student has the disease. The school notified parents that the student has not been on campus since January 27, and so far, officials are unaware of any additional cases within the student body. 

RELATED: Measles case confirmed at St. Pete Catholic High School

The school said it's working with the health department.

Why you should care:

For many local doctors, the reappearance of the virus is a shift in the medical landscape. Dr. Patrick Mularoni, a pediatric ER physician at Johns Hopkins All Children's Hospital, said the absence of the virus for decades has made its return particularly notable for health care providers.

"I've been practicing in the pediatric emergency room for 20 years. I've seen over 50,000 patients, and I have never seen measles," Mularoni said. "That's something I worry about because most providers have never seen it."

RELATED: University of Florida investigating possible measles exposure after cases reported in Alachua County

Now that the virus is back in the community, Mularoni warns that its contagious nature makes rapid spread a near-certainty in unvaccinated populations.

"If you're in a room with somebody with measles, and you're not vaccinated, there's like a 90% chance that you're going to catch it," he explained.

Dig deeper:

The St. Pete case is just one piece of a larger puzzle forming across the state. In Southwest Florida, Ave Maria University is grappling with 20 confirmed cases. Meanwhile, in Gainesville, the University of Florida is performing contact tracing for two classes where exposure may have occurred.

Nationally, the trend is equally alarming. The CDC reported this week that the U.S. has seen 733 cases so far this year. Compared to the historical average of 180 cases per year, the 2026 surge represents a massive spike.

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Experts point to "vaccine hesitancy" as the primary driver.

"Unfortunately, we have less and less people getting vaccinated," Mularoni said. "When the population isn't vaccinated, a condition like measles can spread very easily."

Measles symptoms and incubation

Doctors warn that the long incubation period makes the virus difficult to contain. It can take 7-14 days after exposure before a person feels sick. Initial symptoms often mimic a common cold:

• Runny nose and cough
• Fever
• Red, watery eyes

The "hallmark" measles rash typically doesn't appear until four days after the initial symptoms begin. This means individuals can be contagious before they even realize they have the virus.

What you can do:

The greatest risk is to those who cannot be protected by medicine. Babies are not eligible for the measles vaccine until they reach 12 months of age, leaving them entirely dependent on the "herd immunity" of the adults and older children around them.

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"If you're a parent of a young child or if you've chosen not to vaccinate your children, you should make sure to stay away from sick people right now," Mularoni advised. "We don't know how this is going to spread in the community."

For those who have been vaccinated, doctors said the measles vaccine provides lifelong immunity, and doctors say boosters are not necessary.