In a year that has broken records for the most measles cases since the disease was declared eradicated in 2000, the U.S. has seen 1,123 confirmed cases across 28 states as of July 11, the most since 1992, according to the Centers for Disease Control and Prevention.
Since May 2018, Florida has had 15 measles cases — with three of them coming from Miami-Dade County and one in Broward. And while cases are more rare in the Sunshine State than in California or New York, where outbreaks have resulted in dozens of people infected with measles, Miami-Dade and Broward are among 10 counties in the nation with the highest risk for a measles outbreak, according to a study published in May in Lancet Infectious Diseases.
In fact, Miami-Dade was among the top three counties with the highest risk, after Chicago’s Cook County and Los Angeles County in California. Broward was No. 7 on the list.
South Florida’s risk stems from its high international and immigrant population, medical experts say. Sometimes immigrants entering Miami-Dade and Broward are not vaccinated, or doctors do not have their vaccination records, said Dr. Judy Schaechter, chair of pediatrics at the University of Miami Miller School of Medicine and of Miami-Dade’s immunization coalition.
The national vaccination rate for children entering kindergarten stands at 94.3%, according to the American Academy of Pediatrics; Miami-Dade’s was 93.3% for the 2018-2019 school year, according to the Florida Department of Health. To prevent outbreaks, communities must remain in a “herd-immunity” range of at least 90%.
Some children have conditions that necessitate medical exemptions from vaccination requirements, such as having immunodeficiency or undergoing chemotherapy. Others choose not to vaccinate due to a purported connection between vaccines and autism, a medical myth originating in the 1990s that medical professionals have repeatedly debunked.
In Williamsburg and Borough Park in Brooklyn, a cluster of Orthodox Jewish individuals who had religious exemptions from measles vaccinations led to an outbreak of more than 400 cases. Pamphlets spreading false information about vaccines spurred the immunization boycott.
In Rockland County, about 30 miles north of Manhattan, there were 280 confirmed measles cases as of July 11, and the county has had to renew its emergency order four times to contain the outbreak. The outbreak began about nine months ago when travelers from Israel unwittingly brought the contagious virus with them.
“Maybe fear is more contagious, even than measles,” Schaechter said.
A disease that can spread even before symptoms emerge, measles is five times more contagious than the flu, said Dr. Fernando Mendoza, who serves as medical director of the Children’s Emergency Center at Baptist Children’s Hospital.
Measles, normally a childhood infection that can be prevented with the MMR vaccine, can be serious. Children younger than 5 and adults 20 and over, plus pregnant women and people with compromised immune systems are most at risk for developing serious complications, including pneumonia and encephalitis, according to the CDC.
Measles cases often originate outside of the U.S., and proximity to major international airports puts communities at risk. Miami International Airport and Fort Lauderdale-Hollywood International Airport are two potential entry points for measles cases in South Florida.
“A plane is a giant metal tube of germs swirling around in recycled air,” Mendoza said. “If you sneeze or cough, there’s a droplet that stays suspended in the air. That droplet can stay in the air for hours after the patient has left the room.”
The four Florida cases from the past year and a half were all unvaccinated residents who were exposed to measles while traveling internationally, according to the Florida Department of Health. The three Miami-Dade cases were children, and the Broward case was an adult.
Both Schaechter and Mendoza encourage all parents to ensure their children are vaccinated.
“We have an obligation to make sure they don’t pick up measles from us, and we need to protect ourselves and our families,” Schaechter said.