Jackson County Public Health in Missouri has confirmed a measles case in a vaccinated resident of eastern Jackson County. The department is working to reach people who were at its Lee's Summit building and at two businesses in Overland Park, Kansas, while the person was infectious.
The department said the resident will stay isolated until no longer infectious, no other cases have been identified, and the risk to the general public is considered low. The person appears to have been exposed outside Jackson County, and the investigation is ongoing.
Where and When the Exposures Occurred
The person was at the Jackson County Public Health building at 3651 NE Ralph Powell Road in Lee's Summit on Tuesday, Sept. 8, from 8 a.m. to noon, and on Thursday, Sept. 10, from noon to 4 p.m., for unrelated services, according to Jackson County Public Health. The department closed the building on Monday, Sept. 14, to identify staff and clients who were there during those times and check their immunity status. It said the building would reopen at 8 a.m. Tuesday.
On Monday, Sept. 7, the person also visited two locations in Johnson County, Kansas: Kyoto Sushi and Steak, at 6792 W. 135th in Overland Park, from noon to 4:30 p.m., and Pan-Asia Supermarket, at 12035 Metcalf in Overland Park, from 2 to 5:30 p.m.
Bridgette Shaffer, health director at Jackson County Public Health, said the department's "top priority" is making sure anyone who may have been exposed has the information needed to protect themselves and their families. She said the department is coordinating closely with the state health department.
Measles spreads through the air when an infected person breathes, coughs, or sneezes, and the virus can stay in the air for up to two hours after that person leaves. That is why being in the same store or restaurant can count as an exposure, even without close contact.
Charlie Hunt, director of the Johnson County Department of Health and Environment, said employees at the two businesses are easy to reach, but tracking down customers is much harder.
Why Preventive Treatment Timing Matters
For the Kansas exposures, the window for preventive treatment has likely passed. "It's probably at this point too late to prevent measles if they were exposed," Hunt told KCTV. He explained that the vaccine must be given within 72 hours of exposure to prevent illness and that immune globulin can be given within six days. The Kansas exposures happened on Sept. 7, so both windows have closed.
That does not make vaccination pointless. Hunt said the department still recommends that exposed people who are unvaccinated get the MMR vaccine, and that testing generally is not done unless someone develops symptoms.
The Lee's Summit exposure on Sept. 10 was more recent. Anyone who was there during that window and is pregnant, has a weakened immune system, or is unvaccinated should contact a health care provider or the health department right away rather than assume the treatment window has closed.
Hunt said the department is less concerned about people who are fully vaccinated and more concerned about infants who are too young to be vaccinated and older people who have not been vaccinated. He said Johnson County has alerted the Kansas Department of Health and Environment and has started contact tracing.
Breakthrough Cases Are Uncommon and Usually Milder
The fact that the patient was vaccinated is easy to misread.
Jackson County Public Health said breakthrough measles cases in vaccinated people are rare but can happen because no vaccine is 100% effective. Vaccinated people who get measles usually have milder illness and are less likely to spread the virus to others, although measles remains highly contagious.
National data support that. According to the CDC's measles case data, two MMR doses are 97% effective at preventing measles, and one dose is 93% effective. The CDC notes that breakthrough infections can occur, especially in communities with outbreaks where a lot of virus is circulating. MMR coverage among U.S. kindergartners has fallen from 95.2% in the 2019-2020 school year to 92.4% in the 2025-2026 school year.
Hunt said the country is in the middle of a large measles resurgence and urged people to get vaccinated.
Symptoms and When to Call
Jackson County Public Health said measles symptoms typically appear seven to 14 days after exposure. Hunt said symptoms usually appear about 11 to 12 days after exposure but can take as long as 21 days.
Symptoms can include high fever, cough, runny nose, red and watery eyes, and Koplik spots, which are small white spots inside the mouth. A rash usually appears three to five days after the first symptoms, starting on the face and spreading down the body. The CDC's measles symptoms and complications page has more detail.
Health officials advise anyone who was at the listed locations during the listed times to:
- Watch for symptoms for 21 days after exposure and contact their local health department if symptoms develop.
- Stay isolated for 21 days if unvaccinated. People who have received at least one measles vaccine dose do not need to isolate.
- Contact a health care provider or the health department immediately if unvaccinated and pregnant or immunocompromised, since measles immune globulin given within six days of exposure can help prevent illness or make it less severe.
- Call ahead before visiting a doctor's office or emergency room if symptoms develop, so staff can take steps to protect other patients.
Children younger than 5, especially infants too young to be vaccinated, pregnant women, and people with weakened immune systems face a higher risk of serious complications.
Jackson County Public Health runs a measles hotline at 816-404-9889, Monday through Friday from 8 a.m. to 4 p.m., for questions about exposure, symptoms, or vaccination status. Johnson County residents can call the Johnson County Department of Health and Environment at 913-826-1303. Jackson County has also posted an online survey to help people assess exposure risk.
Both departments are continuing their investigations. Because symptoms can take up to 21 days to appear, people exposed on Sept. 10 will remain in the monitoring window until about Oct. 1. MedicalDaily will report any additional confirmed cases or exposure sites.
Key Questions Answered
What happened? Jackson County Public Health confirmed a measles case in a vaccinated resident of eastern Jackson County and named exposure sites in Lee's Summit, Missouri, and Overland Park, Kansas.
Where were the exposures? The Jackson County Public Health building at 3651 NE Ralph Powell Road on Sept. 8 from 8 a.m. to noon and Sept. 10 from noon to 4 p.m., plus Kyoto Sushi and Steak and Pan-Asia Supermarket in Overland Park on Sept. 7.
Can vaccinated people get measles? Yes, but it is rare. Two MMR doses are about 97% effective. Breakthrough cases are usually milder and less likely to spread.
Is it too late for preventive treatment? For the Sept. 7 exposures in Kansas, yes, since the vaccine must be given within 72 hours and immune globulin within six days. Vaccination is still recommended for unvaccinated people to protect against future exposure.
What symptoms should people watch for? High fever, cough, runny nose, and red, watery eyes, followed three to five days later by a rash that starts on the face and spreads downward.
How long should people monitor? For 21 days after exposure. Unvaccinated people should isolate during that time, while people with at least one vaccine dose do not need to.
Who should call a provider right away? Anyone who is unvaccinated and pregnant or immunocompromised, since immune globulin given within six days of exposure can help. Anyone with symptoms should call ahead before visiting a clinic or emergency room.
