This year, the USA has reported 704 confirmed measles cases in 22 states, compared to 372 cases in 2018, 120 cases in 2017 and 86 cases in 2016.
A new study suggests four Florida counties, including Orange County, are at high risk for a measles outbreak.
The results were published yesterday in the peer-reviewed journal Lancet Infectious Diseases.
To compile the map, analysts counted nonmedical vaccine exemption rates per county and compared those to each county's rate of travel, population size, and proximity to other global measles outbreaks.
Miami-Dade County was listed as number three while Broward County took seventh place. "It is therefore critical that we proactively identify areas most likely to experience outbreaks to strategically target for surveillance and control".
The number of confirmed measles cases in the USA has almost doubled since past year, with more than 700 cases since January 2019, and researchers warned the epidemic could worsen. Travelers are coming to the US from measles-stricken countries.
The recent spike in cases, the researchers say, is due to reintroduction by worldwide travelers from countries experiencing measles outbreaks, compounded by low-vaccination rates in certain localities, which an increasingly visible anti-vaccination movement fuels.
The analysis correctly predicts the regions in Washington, Oregon, and NY that have already seen major measles outbreaks this year.
"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", says the study's other corresponding author, Sahotra Sarkar, professor of philosophy and integrative biology at the University of Texas at Austin. Furthermore, 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. The study's authors said travel from countries including India, China, Mexico, Japan, Ukraine, Philippines and Thailand appeared to pose the greatest measles risk. They added that viruses only need a small, self-contained pocket of people to thrive, and cited Brooklyn's tiny, mostly unvaccinated Orthodox Jewish population as an example.
Additional authors are from the University of New South Wales Sydney and St. Michaels Hospital in Toronto.