It may be a new year, but the mumps outbreak that began in Arkansas last summer continues to grow as state health officials put the tally at 2,416 cases under investigation as of Jan. 3.


Just a few short months ago, the state saw less than 200 cases and the Arkansas Department of Health (ADH) said the numbers could double in coming weeks. It’s done that and more.

As of today, Benton, Carroll, Conway, Crawford, Faulkner, Lonoke, Madison, Pulaski, Sevier, and Washington are the counties involved. There are currently 40 workplaces, 38 schools in 9 school districts, 3 colleges/vocational schools, and 3 private schools impacted, the ADH notes.

LISTEN: Arkansas, mumps and the MMR vaccine: A discussion with Dr Dirk Haselow

Concerning the MMR vaccine, ADH officials say throughout this outbreak, 90% to 95% of school-aged children and 30% to 40% of adults involved in the outbreak have been fully immunized. The vaccine is not perfect. Two doses of the MMR shot are about 88% effective at preventing the mumps. That means that if you have 100 people who are fully vaccinated, 88 of them will be fully protected. The remaining 12 will still be vulnerable to mumps.

If it were not for the vaccine, however, we would be seeing many, many more cases of the mumps. Also, we have only seen a few cases with complications, like swelling of the brain or testicles. Normally, we would expect to see many more persons with complications. This tells us that even though some vaccinated individuals are still getting the mumps, they are experiencing mild disease. The vaccine remains the best protection we have against the mumps.