Hennepin County is among the 25 counties across the United States that are at greatest risk for new outbreaks of measles in 2019, according to a risk analysis published in the journal Lancet Infectious Diseases.
The analysis is based not only on the population and size of the counties, but on two other key factors: the presence of an international airport, which increases the likelihood that infected travelers from countries with measles will pass through the area, and a low-vaccination rate among young people due to a high number of non-medical exemptions.
Unlike most of the other counties identified in the analysis, Hennepin County — indeed all of Minnesota — has not had a single reported case of the measles this year. But it is still at high risk for an outbreak and “should be targeted for enhanced surveillance and enhanced vaccination efforts,” according to the authors of the analysis.
“There has been a resurgence of measles cases, among other vaccine preventable diseases, in the U.S. and other countries in recent years,” says Lauren Gardner, one of the authors of the analysis and an associate professor of civil engineering at Johns Hopkins University, in a released statement. “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.”
The number of measles cases reported in the U.S. this year is nearing 800 — the most since 1994 and since measles was declared eliminated in the country in 2000, according to the Centers for Disease Control and Prevention. Individual cases have been reported in 23 states, and outbreaks (three or more cases) are currently ongoing in six states (California, Georgia, Maryland, Michigan, New Jersey and New York).
The majority of Americans who have become infected were unvaccinated against the disease.
Most likely sources
Health officials believe the measles risk will likely grow this summer as international travel increases, bringing more opportunities for the disease to enter the U.S. Indeed, last week, the World Health Organization reported that more than 34,000 cases of measles were documented in Europe during just the first two months of 2019. Those cases included at least 13 deaths.
But according to the analysis by Gardner and her colleagues, the countries that pose the greatest measles risk to the U.S. are (in order of risk) China, Mexico, Japan, Ukraine, the Philippines and Thailand. Only one of those countries (Ukraine) is European.
It’s important to also note that tourists and businesspeople traveling between those countries and the U.S. — not immigrants — are the source of the risk described in the new analysis.
“We should consider measures to improve public health in these countries — for instance, foundations that are committed to global health enhancement could allocate funding for vaccination efforts in these countries,” Gardner and her colleagues stress.
[image_credit]CDC[/image_credit][image_caption]Expected relative size of a measles outbreak[/image_caption]Where risk is greatest
Here are the 25 counties that the researchers predict are at the highest risk of measles outbreaks in 2019. Thirty of the 45 counties that have reported measles cases this year are either on this list or are adjacent to one of the counties on the list.
- Cook, Illinois
- Los Angeles
- Miami-Dade, Florida
- Queens, New York
- King, Washington
- Maricopa, Arizona
- Broward, Florida
- Clark, Nevada
- Harris, Texas
- Honolulu
- Wayne, Michigan
- Tarrant, Texas
- Multnomah, Oregon
- Orange, Florida
- Essex, New Jersey
- Denver, Colorado
- Hillsborough, Florida
- San Mateo, California
- Salt Lake, Utah
- Suffolk, Massachusetts
- Clayton, Georgia
- Travis, Texas
- Hennepin, Minnesota
- Loudoun, Virginia
- San Diego
FMI: You’ll find the analysis on the website for Lancet Infectious Diseases.
