• Nine confirmed measles cases reported in Williams County, North Dakota, all among unvaccinated individuals.
• 180 students are isolating for 21 days after potential exposure in Williston schools.
• Health officials recommend early MMR vaccination for infants and children in Williams County to combat the outbreak.

A measles outbreak has been declared in Williams County, North Dakota, marking the first occurrence of the disease in the state since 2011. As of the latest reports, nine confirmed cases have been identified, all affecting unvaccinated individuals. The outbreak has particularly impacted schools in Williston, leading to the isolation of 180 students. Health officials are actively conducting vaccination clinics and revising immunization recommendations to mitigate the spread of the highly infectious disease.

• What: A measles outbreak has been declared in Williams County, North Dakota, leading to confirmed cases and isolation measures.
• Who: The outbreak primarily affects unvaccinated individuals, students, and staff in the Williston Basin School District. Key figures include Molly Howell (immunization director at North Dakota Health and Human Services), Lynn Douglas (district nurse), and Jason Germundson (Superintendent).
• When: The outbreak was reported in early May 2025. The first case since 2011. Isolation period is 21 days. Revised vaccine recommendations are effective immediately.
• Where: The outbreak is centered in Williams County, North Dakota, specifically impacting schools in Williston.

The measles outbreak in Williams County highlights the importance of vaccination in preventing the spread of infectious diseases. The prompt response from state health officials and the Williston Basin School District, including vaccination clinics and isolation measures, demonstrates a coordinated effort to contain the outbreak. The revised immunization recommendations, particularly for infants, reflect an adaptive strategy to protect vulnerable populations. The effectiveness rates of the MMR vaccine, 93% with one dose and 97% with two doses, underscore its crucial role in preventing measles.

"These were the first cases that we've had reported since our last case which was in 2011."

“There’s concern any time there’s an outbreak, and this is considered a measles outbreak in our community.”

“We’re trying to mitigate as many risks as we can. We have a list of kids who aren’t vaccinated, and we’ve called them saying they’ve been potentially exposed and need to stay home for 21 days. That’s what the state recommends,”

The measles outbreak in Williams County, North Dakota, has grown to nine confirmed cases, marking the state's first outbreak since 2011, with health officials tracing the spread to community transmission within Williston schools. The majority of cases are among unvaccinated individuals, prompting concerns about declining vaccination rates in the region. In response, health authorities have implemented isolation measures, with approximately 180 unvaccinated students from Missouri Ridge Elementary, Williston Middle School, and Williston High School quarantining for 21 days. Vaccination clinics are underway in Williston, and revised immunization recommendations include early MMR vaccination for infants aged 6 through 11 months and an early second dose for children. Health officials are working to prevent further spread and are urging residents and travelers to ensure they are vaccinated against measles. The situation highlights the critical role of vaccination in preventing measles and the need for continued public health vigilance.