Seven people have been diagnosed with measles in an outbreak that started at the Manatee Bay Elementary School in Weston, Florida.
The Florida Department of Health in Broward County announced in a notice to local health care providers on Feb. 16 that a third grader with no history of travel had been diagnosed. Three other measles cases at the elementary school were confirmed on Saturday, followed by one each on Monday and Tuesday.
The latest case to appear in the state's surveillance system is a child 4 years old or younger — the first case outside the school. Of the other six cases, three were in children ages 5 to 9, and three in those 10 to 14.
The county health department issued an advisory Sunday saying that it was “working with all partners, including Broward County Public Schools and local hospitals, to identify contacts that are at risk of transmission.”
The Florida Department of Health has not recommended that all the school's students — or even just unvaccinated ones — stay home, as is generally done in such outbreaks. Instead, it is "deferring to parents or guardians to make decisions about school attendance," according to a letter Tuesday from Joseph Ladapo, the state's surgeon general.
It’s not publicly known whether those infected were vaccinated, NBC 6 South Florida reported. Two doses of the measles-mumps-rubella (MMR) vaccine are 97% effective.
John J. Sullivan, communications and legislative affairs officer for the Broward County Public School District, said in a statement on Friday that "the school will continue with all the preventative measures that have been implemented, such as enhanced cleanings at the school, and remains in communication with its families."
Manatee Bay Elementary School referred NBC News to the school district for information about the outbreak.
The health department in Broward County said in a statement that it was "carrying out an epidemiological investigation" of the measles outbreak and working to identify close contacts of those diagnosed, but that "all details regarding the investigation are confidential."
In the 2022-23 school year, Florida’s statewide MMR vaccination rate was around 91%, compared to the national rate of 93%, according to a report from the Centers for Disease Control and Prevention. The U.S. rate has declined from 95% since the 2020-21 school year. The World Health Organization considers 95% the threshold necessary for herd immunity from measles.
Measles is highly contagious. Symptoms typically begin to appear a week or two after infection, and can include a cough, runny nose, fever and red, watery eyes. Small, white spots may appear inside the mouth a couple days later, followed by a rash consisting of flat, red spots that start on the face and spread to the neck, torso and limbs.
One in 5 unvaccinated people in the U.S. who get measles are hospitalized with severe complications. As many as 1 in 20 children with measles develop pneumonia, the leading cause of death for those in the age group who get the disease. People who are unvaccinated or immunocompromised also face a risk of swelling in the brain or death.
As of Thursday, 35 measles cases had been reported across 15 states already this year, including an outbreak of at least eight cases in Philadelphia last month, according to the CDC. Last month, the agency issued a warning to health providers to be on the lookout for more cases. Last year, 58 cases were reported in total.
Dr. Charles Mitchell, a professor of pediatric infectious disease at the University of Miami Miller School of Medicine, said the recent measles outbreaks may be the result of growing vaccine hesitancy.
“My suspicion is that there is unfortunately some questioning of utility or the acceptance of vaccines,” Mitchell said Tuesday afternoon. “I think going forward, I would not be surprised if we begin to see the recurrence of these cases. I mean, the fact that you have five cases of measles at this one elementary school suggests to me that the rate of vaccination may have fallen off.”
Mitchell emphasized that the MMR vaccine is especially crucial because there aren’t any treatments or cures for measles.
“I suspect that some people have lost their fear,” Mitchell added. “I don’t think they remember what it was like back in the ’60s or ’70s.”