WATCH: Immunization expert sheds light on mumps across US

FILE - In this Thursday, Jan. 29, 2015 file photo, a pediatrician holds a dose of the measles-mumps-rubella (MMR) vaccine at his practice in Northridge, Calif. A new study published in the journal Science suggests the measles vaccine not only prevents measles, but may also help the body ward off other infections. The vaccine was in the spotlight this year after a large measles outbreak linked to Disneyland sickened people in the U.S., Mexico and Canada. (AP Photo/Damian Dovarganes, File)

NASHVILLE, Tenn. (WKRN) – Health officials say there are now at least 278 mumps cases across five counties in Washington State.

The spike is likely tied to a vaccine that can lose its strength over time.

There were more than 100 mumps cases in eight different states in 2016, the most active year for mumps in the U.S. since 2006. Even a student at Belmont University in Nashville was diagnosed.

On Friday, News 2 spoke with Dr. Kelly Moore, the immunization program director with the Tennessee Department of Health, to ask questions and learn more about the mumps.