U.S. health officials say this year’s count of measles cases (including here in Illinois) has surpassed 800, a growing tally that is already the nation’s highest in 25 years.

A new report shows 25 U.S. counties are at risk for a major outbreak, including Cook County here in Illinois, which has the highest risk of any county in the nation, according to the study.

Cook County is listed as the most at-risk, followed by Los Angeles County. While the number of confirmed measles cases remains low — Illinois has a total of seven confirmed measles cases so far in 2019, according to the Illinois Department of Public Health — "because of the presence of major international airports," Cook County and Los Angeles County " could serve as the fulcrum of continuous importation of the measles virus into the USA," according to the study.

Thus far in 2019, a total of 839 cases were reported as of last week. That’s the most since 1994, when 963 were reported for the entire year.

Below are the counties most at risk of a measles outbreak identified in the study:

  1. Cook County, Illinois
  2. Los Angeles County, California
  3. Miami-Dade County, Florida
  4. Queens County, New York
  5. King County, Washington
  6. Maricopa County, Arizona
  7. Broward County, Florida
  8. Clark County, Nevada
  9. Harris County, Texas
  10. Honolulu County, Hawaii
  11. Wayne County, Michigan
  12. Tarrant County, Texas
  13. Multnomah County, Oregon
  14. Orange County, Florida
  15. Essex County, New Jersey
  16. Denver County, Colorado
  17. Hillsborough County, Florida
  18. San Mateo County, California
  19. Salt Lake County, Utah
  20. Suffolk County, Massachusetts
  21. Clayton County, Georgia
  22. Travis County, Texas
  23. Hennepin County, Minnesota
  24. Loudoun County, Virginia
  25. San Diego County, California

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