Where should the greatest focus be on prevention of measles through vaccine and other efforts?

A recent study sought to answer that question, identifying 25 U.S. counties that are most likely to experience measles outbreaks in 2019. The analysis, published in The Lancet Infectious Diseases, is based on international air travel volume, nonmedical exemptions from childhood vaccinations, population data, and reported measles outbreak information.

“There has been a resurgence of measles cases, among other vaccine preventable diseases, in the U.S. and other countries in recent years. Measles, in particular, poses a serious public health threat due to the highly contagious nature of the disease. It is therefore critical that we proactively identify areas most likely to experience outbreaks to strategically target for surveillance and control,” explained corresponding author Lauren Gardner, PhD, an associate professor in the Johns Hopkins Department of Civil Engineering.

The list is topped by Cook County, Illinois, with Los Angeles County, California; Miami-Dade County, Florida; Queens, New York; and King County, Washington, constituting the first five.

The study notes that as of late April, the U.S. has seen more than 700 cases of measles this year, the highest number in decades. By May 10, that number had jumped to nearly 840, according to the CDC.

Researchers emphasize that the recent spike in cases is spurred by international travelers from countries experiencing measles outbreaks coupled with low vaccination rates in certain localities—often related to the antivaccination movement.

“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,” said the other corresponding author, Sahotra Sarkar, PhD, professor of philosophy and integrative biology at the University of Texas at Austin.

Interestingly, the analysis correctly identified regions in Washington, Oregon, and New York that have already seen major measles outbreaks this year.

“Our prediction is aligned with multiple counties that have experienced measles outbreaks this year. 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,” Dr. Gardner said.

Dr. Sarkar recommends that policymakers focus on centers of vaccination resistance, as well as regions with a lot of passenger inflow from affected countries worldwide if there are even small local pockets of unvaccinated people. “The New York borough of Brooklyn is a perfect example with a large number of unvaccinated members of an orthodox Jewish community even though the overall county vaccination rate is not low,” he pointed out.

The CDC notes that at least 45 counties have reported measles cases so far in 2019. The study authors state that 30 of those are either included in the top 25 at-risk counties or adjacent to them.

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