North Dakota Measles Quarantine Expands for the Unvaccinated

North Dakota Health and Human Services (HHS) reports two additional measles cases in Cass County, bringing the state’s total to 11 cases in 2025. Both individuals were unvaccinated and acquired measles through international travel.

HHS stated on May 11, 2025, that exposed vaccinated individuals don’t need to be quarantined.

However, individuals who have not received a dose of the measles, mumps, and rubella (MMR) vaccine should be quarantined (stay home) and monitored for symptoms for 21 days. 

These are not related to recent cases in Williams County.

"Due to the current measles outbreak, please isolate at home if you have symptoms of runny nose, fever, cough, and rash,” said Dr. Beverly Tong, Upper Missouri District Health Unit deputy director, in a press release on May 6, 2025.

“Isolation should continue until at least four full days after the onset of a rash."

"Time from exposure to onset of rash is generally around seven to 21 days, and you can spread measles up to four days before the rash appears. Don't hesitate to contact your health care provider's office if you wish to be tested. They will instruct you on when and where to arrive at their clinic to minimize risk to others."

Because some new measles cases are not linked to earlier known exposures, there is concern about potential community transmission. As a precaution, HHS recommends that all residents and travelers to Williams County ensure they are vaccinated against measles. This includes considering early MMR vaccination for infants aged 6 through 11 months.