A new study reveals the counties across the United States that are most at risk for outbreaks of the measles this year — and large international airports are one characteristic that unites them, researchers said.
Cook County in Illinois, which includes Chicago, tops the list of susceptible areas, followed by Los Angeles in California and Miami-Dade in Florida, according to research published Thursday in Lancet Infectious Diseases. The New York City borough of Queens and Washington’s King County, which is home to Seattle, were the fourth and fifth most at-risk counties.
Researchers from Johns Hopkins University in Baltimore, Maryland, and the University of Texas at Austin said their findings were based on a variety of factors that heighten measles risk — ranging from non-medical childhood vaccination exemptions to extensive international air travel, according to a news release on the study.
The authors also released an interactive online map to show which counties could be in trouble.
“Our prediction is aligned with multiple counties that have experienced measles outbreaks this year,” Lauren Gardner, a study author and Johns Hopkins professor, said in a statement. “Critically, we recommend that public health officials and policymakers prioritize monitoring the counties we identify to be at high risk that have not yet reported cases, especially those that lie adjacent to counties with ongoing outbreaks and those that house large international airports.”
The study comes as the extremely contagious virus — which was declared “eliminated” in the U.S. in 2000 — is back in the news: Measles outbreaks have sickened more than 700 across the U.S. so far this year, according to the Centers for Disease Control and Prevention. That’s more than any other year in decades. And in just a few months, this year’s total reported cases have eclipsed the 667 cases reported in 2014, which was the by far the largest number in the last decade.
Florida’s Broward County came in at No. 7 on the list, followed by Nevada’s Clark County, home to Las Vegas, and Harris County, Texas, home to Houston. Tarrant County in Texas, which includes Fort Worth, was No. 12, while Mecklenburg County in North Carolina, which includes Charlotte, was No. 26.
Major airports were a common thread among the counties that made the top of the list, with Cook County hosting two — O’Hare and Midway, which are both large and international.
Hosting the world’s busiest airport — Hartsfield-Jackson International in Atlanta — helped put Georgia’s Clayton County on the list at No. 21, despite the state’s relatively strong rates of vaccination against the virus, according to the Atlanta Journal-Constitution. U.S. Customs and Border Protection officials said they work with the CDC at ports to make sure international travelers with “overt signs of illness” are flagged before entering the country, according to the newspaper.
International travelers from places like India, China, Mexico, Japan, Ukraine, Philippines, and Thailand are a major reason cases have come to the U.S., according to researchers. But they said that it’s lagging rates of immunization in this country that make the population ripe for the spread of the highly infectious disease.
“Anti-vaxxers are denying the best and very successful medical science we have and choosing instead to rely on fraudulent claims, such as a purported link to autism, that have been uniformly debunked by evidence and analysis over the last two decades,” Sahotra Sarkar, a study author and professor at the University of Texas at Austin, said in a statement.
Just how accurate is the researchers’ analysis?
The study points to Washington state, New York and Oregon as areas of high risk, and those states have already suffered measles outbreaks in 2019, according to the researchers, who said the “vast majority of counties that have reported measles cases as of April 2019 are included in team’s top 25 at-risk counties or lie adjacent to one of the top 25 counties.”
They’ve also been right before: The researchers who worked on the study accurately predicted which places the Zika virus would hit, according to the Chicago Tribune.
Measles cases have been reported in 23 states so far this year, according to the CDC.
“What’s going to happen as we move into the summer months, with all that back-and-forth travel between Europe and the US ... there’s opportunities to introduce a lot more measles into this country,” said Dr. Peter Hotez, dean of the National School of Tropical Medicine at Baylor University’s College of Medicine, according to CNN. “Europe is a disaster right now, even worse than North America, in terms of measles.”